Pole Arm from Underwater Excavation on the Relics of a Bridge at the Slavic Defensive Settlement at Olsborg in Plön, on the Großer Plöner See Lake, Northern Germany

Großer Plöner See is located between Kiel and Lübeck, in the central part of the socalled Holstein Switzerland. The island hillfort of Plune (Olsborg) appears for the first time in the source information of the chronicler Adam Bremen in 1070. At the Olsborg hillfort island 15 spearheads and javelins were discovered excavated from a small area of investigated bridge debris. This assemblage falls, in the light of dendrochronological research, between the late 10th and late 11th centuries. However, taking into account the information from written sources about the German conquest of Vagria and the destruction of the hillfort in 1138–1142, it can be presumed that also in those years some of the pole arm discovered there may have been lost in the area of the bridge.Jezioro Großer Plöner See leży między Kilonią a Lubeką, w centralnej części tzw. Szwajcarii Holsztyńskiej. Wyspowy gród Plune (Olsborg) pojawia się po raz pierwszy w informacji źródłowej kronikarza Adama Bremeńskiego w 1070 r. Przy wyspie grodowej w Olsborgu odkryto 15 grotów włóczni i oszczepów, wydobytych na niewielkiej powierzchni badanego rumowiska mostu. Zespół ten mieści się w świetle badań dendrochronologicznych w przedziale lat od końca X do końca XI w. Zważywszy jednak na informacje ze źródeł pisanych o niemieckim podboju Wagrii i zniszczenie grodu w latach 1138–1142, można domniemywać, iż również w tych latach mogły być utracone w rejonie mostu niektóre z odkrytych tam egzemplarzy broni drzewcowej

„Żyjące mosty” w średniowiecznych miastach Europy

Lying within the borders of the former Roman Empire, medieval Europe took on a cultural legacy that included a network of highly organised roads and bridges, which made this great political organism function so smoothly for hundreds of years. According to current estimates, there may have been around 40,000 bridges on the roads of the Empire, mostly built of wood. Only some of the bridges were stone structures. After the fall of the Empire, however, many roads and bridges vanished from the landscape, since maintaining their technical efficiency was no longer workable. Nevertheless, many structures built entirely of stone survived into the Middle Ages, and sometimes even into the present day. Only the wooden bridges, the largest number of which used to span the banks of smaller rivers and streams, have not stood the test of time. Europe had to wait several hundred years more for new stone bridges to be built, as the renaissance of some roads and bridges, undoubtedly linked to the development of medieval towns, was not observed in Europe until the 11th and 12th centuries. This stemmed from the fact it took so long for the professions of stonemasons and builders to be revived – they had to acquire the necessary knowledge anew, using mainly empirically acquired skills. It was also vital that the preserved Roman bridges could serve as an excellent model for builders of similar structures in medieval times. The construction of new stone bridges is evidence by almost 600 smaller and larger stone bridges built in France alone between the mid-11th century and the mid-14th century; and we may speculate that also thousands of wooden bridges were constructed at the time. It is worth recalling at this point that all these investments coincided with the construction of the famous Gothic cathedrals in many European states. The same stonemasons would be often involved in the construction of both bridges and cathedrals. As numerous examples show, medieval builders, however, did not passively process Roman models. In addition to employing construction traditions, they developed vaults in the form of strongly flattened arches, with a circular section smaller than a semicircle, sometimes elliptical vaults and, in the spirit of the new Gothic architecture, pointed arch vaults. Bridges have always been among the most essential elements of the spatial, communication organisation of medieval, and later, European towns. It is in them that human will to overcome natural boundaries, people’s desire to subdue space divided or fragmented by the current of a river is most vividly evidenced. This is why the architecture of bridges is one of the most individual, foregrounding features that identify urban space. The history of medieval inner-town bridges is linked not only to all spheres of human activity: construction and economy, politics and wars, and finally religion and law, but also to factors completely beyond human control, including various natural disasters. Hence the bridges of this time, like no other architectural works of man, reflect not only existence and culture, but their narrow ribbons also concentre the history of towns in all the variety of minor and major events. The construction of inner-town bridges has always been accompanied by an extraordinary aura, resulting from their unique position in the architectural and urban expression of the urban fabric. It was important for the economic life of the town that the crossings not only served the movement of pedestrians, horses and carts. Bridges within the towns often occupied their central, key points, leading to royal and princely residences, cathedrals, parish churches or, last but not least, town squares and town halls that could not be bypassed. In general, a narrow ribbon of a bridge led shoppers straight to the free-standing stalls of traders, merchants and craftsmen selling various products as well as to the brokers, moneychangers and usurers, whose services were popular in the large medieval towns. Also, the limited walled area of the former towns made bridges an attractive area for the erection of residential houses along their roadways, with shops, exchange offices or workshops on the ground floor facing the roadway.  In this paper, we will barely discuss the bridge as an engineering work, which reduces it to its main function related to communication. Instead, we will focus our attention on the extra-communication roles of the bridge, commercial and residential, which were frequently inextricably linked. Identified on a daily basis with their ‘living’ image, bridges were constituted by those who lived and worked on them, produced a variety of goods and enjoyed their cultural and entertainment activities there.   Located on an island in the Seine, medieval Paris used to boast the most remarkable group of bridges performing commercial and residential functions. The island has always been linked by bridges. The two oldest ones, the Grand Pont and the Petit Pont, were mentioned as early as in the 11th century. The Pont St.-Michel bridge, built at the end of the 14th century, and the Pont Notre Dame, built at the beginning of the 15th century, complete the list of bridges of medieval origin, but these were constructed slightly later on new sites. Other Paris bridges include the Pont-aux-Meuniers and Pont-aux-Changeurs. These two took over the tasks of the old bridge, the Grand Pont, which was destroyed by a violent fire in 1621. With its numerous mills, the former only residually fulfilled transportation functions, while the latter took over commercial and residential activities. At the start of their existence, all the Parisian bridges were wooden structures and as such were repeatedly destroyed by war and natural disasters such as fires, but first of all by countless floods and ice floes. Quite early on, some of these bridges were replaced by stone structures; by the early 12th century, the Grand Pont was already built of stone. The roadways of the Parisian bridges were variously occupied: starting from numerous free-standing booths and market stalls to buildings with shops and workshops on their ground floors facing the roadway and flats on the opposite side of the buildings, facing the Seine. There was no one pattern of how the houses were placed on bridges: sometimes they were located singly on the bridge piers, as the ones on the Grand Pont, but most often the houses formed strings of compact buildings, on both sides of the bridges. In terms of house types, some bridges housed only single-storey buildings (Pont-aux-Changeurs), while others had two-storey (Pont St.-Michel and Pont Notre Dame) or even four-storey houses. The latter were erected on the new bridge in Paris, known as the ‘Pont-au-Change’, which replaced the Pont-aux-Changeurs bridge destroyed by flooding in 1621. The old, house-built Parisian bridges generally disappeared at the end of the 18th century, which was related to the new modernisation project of Paris, including the demolition of the houses on the bridges and the construction of new waterfronts.           In Florence, too, of the four medieval bridges over the Arno River connecting opposite parts of the town, two were built-up structures. One of them, the Ponte Vecchio, built in 1345 to replace the old bridge destroyed by a flood, still stands today as a more than 100 metres long structure, with three symmetrical arches. Its compact two-row development, with a considerable width of 19 m, is dominated by three-storey houses. Their ground floors housed dozens of goldsmith and jewellery shops.             The Ponte delle Grazie bridge represented a slightly different variant of residential development, with single houses (small, single-storey buildings) situated along the bridge roadway, on both sides of all six piers. This nine-span stone road-crossing location on the river with semi-circular vaults was built in 1237.             The longest built-up bridge fulfilling commercial, residential and public functions in medieval Europe was London's Old Bridge, located near the medieval royal Tower castle. Approximately 276 m long, this all-stone structure was supported by 19 ogival vaults of varying spans, ranging between 4.6 and 10.5 m, raised on variously sized piers ranging from 4.60 to 10.67 m. London’s Old Bridge was built between 1176 and 1209, and as early as the 14th-century written sources tell us that at that time, its both sides housed 138 residential structures, with merchant counters and various workshops occupying their ground floors. The houses were arranged in eight compact, single-row blocks, four on each side of the structure. Royal death sentences were also publicly executed on the bridge. The increase in navigation on the river led to calls for the structure to be completely demolished as early as in the 18th century. In 1820, another design for a new five-span bridge was drawn up, which was realised between 1831 and 1834, not far from the Old Bridge. It was also at this time that the crossing, which had functioned there for more than 600 years, was completely demolished.       The last of the bridges under discussion, operating in the major conurbations of medieval Europe, is the Venetian Ponte di Rialto, spanning the banks of the Canal Grande. Unlike other bridges, The Rialto Bridge had never fulfilled a residential function, but carried only merchant stalls at all times. In the early phases of the Middle Ages, a number of wooden bridges were erected in this spot. In the mid-15th century, wooden stalls were added on either side of the bridge roadway, open to its main communication route, where traders in books, sweets and perfumes displayed their goods. However, the wooden bridge needed successive repairs, so it was a decision was taken to erect a stone structure, which was indeed completed in 1591. Since then and until the present day, Ponte di Rialto has presented itself as a bridge with a great carrying arch, spanning 28 metres. Three passageways cross it on both sides, two external and one internal, and two rows of small shops, a total of 24 merchant counters, occupy the bridge, 12 on each side. Today, these shops are still dominated by the sale of goldsmiths' wares, fine porcelain and various Venetian souvenirs. In Germany, the most outstanding example of a 'living' bridge, fulfilling commercial and residential functions is the so-called Krämerbrücke in Erfurt, spanning the Gera River. The large urban agglomeration on both banks of the river was originally connected by a number of wooden bridges, which were not spared by fires or floods, hence a decision to build a massive stone structure on the same site. In 1325, the 78 m long, six-span structure with barrel vaults was completed. On the bridge, along the roadway, 62 single-storey timber-framed houses were located, with traders' and craftsmen's stalls occupying the ground floors. The width of the houses with stallholders' counters could not exceed 2.8 metres. Furthermore, two brick churches were erected above the abutments, closing off the entrance to the bridge through their gate towers. After the fire of 1472, some 60 timber-framed buildings were reinstated on the bridge in two rows. This time these were two- and three-storey building units, with merchant counters on the ground floor. Subsequent renovation work and alterations to the buildings, which took place between the 17th and 19th centuries, replaced the previous circa 60 houses with stalls on the ground floor with 32 three-storey buildings, much wider than before, mostly 5.5–6.0 metres wide, present to this day. It was not until 1997–2002 that a very extensive programme was carried out to restore the bridge to its full architectural splendour. After all this lengthy restoration and adaptation work, the houses on the bridge were given a completely fresh design. In the ground-floor rooms of the buildings, the tradition of the former bridge stalls is today maintained by shops and various galleries, as well as numerous cafés and wine stores. All these shops and their activities are still part of the intensely ‘living’ image of the Krämerbrücke. The so-called Innerebrücke, one of the two main bridges in Esslingen, located in the south-western part of Germany, provides another interesting example of a bridge with commercial and residential functions. This 230 m-long stone structure, supported by 10 semicircular arched spans, was based in the central part, at a length of about 150 m, directly on Die Maille Island. The origins of the structure date back to as early as the mid-13th century; it was probably built in 1286. From its very beginnings until the present day, the Innerebrücke has been associated with trade, crafts and industrial production as well as with the wooden houses and a variety of stalls owned by merchants, traders and craftsmen. However, there is no information that there were permanent residential buildings on the bridge at this time. This is the picture of the bridge as reported by written accounts up to the 17th century. Multi-storey houses on the bridge were erected after this time. As to the bridge's commercial function, it is worth noting again its location. The Innerebrücke connected the main suburbs of the town with its oldest core, i.e., the market square with the town hall and several churches in its vicinity. This location ensured all-day traffic on the bridge and thus the opportunity to trade and shop, so this pulsating facility grew to become the most important artery of the town, both commercially and in terms of transport.             Another bridge, one of the most famous 'living' bridges in Germany, is located in Bad Kreuznach, in Rheinland-Pfalz, in the western part of Germany. The houses on the Altebrücke bridge were not located on the bridge roadway, but only on its piers. Originally, the bridge connected two parts of a new town, located here as early as the 11th century, separated by two arms of the Nahe River, flowing at the bottom of a vast valley. Known as the Altebrücke, the bridge was constructed between 1300 and 1311. With a total length of about 135 m, the stone structure was supported by eight semicircular arched spans. Today, the old, preserved part of the crossing is only about 86 m long. What was special about the bridge, however, was not its construction or location, but the houses standing on its piers, which are mentioned in historical sources as early as 1495. Written sources show that at that time all the piers of the bridge were built up with houses, often on both sides. Numerous wars, floods and house fires have left only three houses on the bridge piers intact. These two-, three- and, in one case, four-storey buildings still embody the concept of a ‘living’ bridge, where its inhabitants live and work. The ground-floor parts of the buildings house various commercial and service facilities, and the upper floors, including the attics, are occupied by studios, warehouses and flats. Another bridge in Germany, called the Alte Fuldabrücke, was located in Kassel, but it has not survived to the present day. It is known to us only from some written accounts, old paintings and contemporary painted reconstructions. The information about the construction of the residence of the Thuringian landgraves and its connection to the opposite bank, where the old town was located, by a bridge, date from 1277. This wooden structure was repeatedly destroyed by floods and hence, between 1509 and 1512, an all-stone crossing was built in place of the old wooden one, with four rather flat vaulted arches, two larger and two smaller, resting on three stone piers and two abutments. The bridge was up to 60 m long. An analysis of old engravings suggests that houses were located on its three piers. The Alte Fuldabrücke functioned continuously on the same spot for hundreds of years, first as a wooden structure and later as a stone one. In 1792, after the construction disaster of the bridge pier, the entire bridge structure, including the houses, was demolished, and any further reconstruction abandoned. Returning to the 'living' bridges fulfilling non-communicative functions, it should also be noted that the 19th century saw not only rampant industrialisation and unprecedented urbanisation of European towns, but it was also a period which left little space for the continued existence of fortified town precincts and tightly built bridges. And although the idea of bridges with residential and commercial functions seemed to have lost its raison d'être forever, recent technologies and materials have now made it close and inspiring again for many bridge builders and architects. This new development trend has become particularly relevant in highly urbanised urban centres, where the only empty spaces left for further, unhindered building development are those along rivers and canals. Although we have information on more than 80 European medieval bridges fulfilling residential, commercial and sometimes public functions, only a small proportion of these, a mere 15 structures, are discussed in this study. Among them are probably those best known, existing in the largest metropolises of medieval Europe and in some larger and smaller German towns. In addition to the above-mentioned tasks, all of the bridges were naturally river crossings in urban agglomerations, spanning their opposite parts divided by rivers, sometimes also combining many fragmented spatial elements of the town into one coherent organism. The history of all these bridges, which were occupied by buildings for hundreds of years, has shed some light on the extraordinary phenomenon of bridge-building. They existed throughout the European Middle Ages and, in many cases, have survived in historic towns right up to the present day, sometimes retaining their commercial, residential and public functions. It is worth mentioning that the idea is now being revived in several corners of Europe. Time will tell whether this medieval concept of a 'living bridge' will blend into the landscape of modern city districts, or whether it will remain on the designers' drawing boards only as a bold utopia and a benevolent vision.Średniowieczna Europa, leżąca w granicach dawnego imperium rzymskiego, przejęła w spuściźnie kulturowej m.in. sieć bardzo dobrze zorganizowanych dróg i mostów. To właśnie one sprawiły, iż ten wielki organizm polityczny funkcjonował tak sprawnie przez setki lat.   Według obecnych szacunków, na drogach imperium mogło funkcjonować około 40 tysięcy mostów, przy czym tylko niewielką część z nich stanowiły konstrukcje kamienne, większość zbudowana była bowiem z drewna

Gas transfer through clay barriers

Gas transport through clay-rocks can occur by different processes that can be basically subdivided into pressure-driven flow of a bulk gas phase and transport of dissolved gas either by molecular diffusion or advective water flow (Figure 1, Marschall et al., 2005). The relative importance of these transport mechanisms depends on the boundary conditions and the scale of the system. Pressure-driven volume flow (“Darcy flow”) of gas is the most efficient transport mechanism. It requires, however, pressure gradients that are sufficiently large to overcome capillary forces in the typically water-saturated rocks (purely gas-saturated argillaceous rocks are not considered in the present context). These pressure gradients may form as a consequence of the gravity field (buoyancy, compaction) or by gas generation processes (thermogenic, microbial, radiolytic). Dissolved gas may be transported by water flow along a hydraulic gradient. This process is not affected by capillary forces but constrained by the solubility of the gas. It has much lower transport efficiency than bulk gas phase flow. Molecular diffusion of dissolved gas, finally, is occurring essentially without constraints, ubiquitously and perpetually. Effective diffusion distances are, however, proportional to the square root of time, which limits the relevance of this transport process to the range of tens to hundreds of metres on a geological time scale (millions of years). 2 Process understanding and the quantification of the controlling parameters, like diffusion coefficients, capillary gas breakthrough pressures and effective gas permeability coefficients, is of great importance for up-scaling purposes in different research disciplines and applications. During the past decades, gas migration through fully water-saturated geological clay-rich barriers has been investigated extensively (Thomas et al., 1968, Pusch and Forsberg, 1983; Horseman et al., 1999; Galle, 2000; Hildenbrand et al., 2002; Marschall et al., 2005; Davy et al., 2009; Harrington et al., 2009, 2012a, 2014). All of these studies aimed at the analysis of experimental data determined for different materials (rocks of different lithotype, composition, compaction state) and pressure/temperature conditions. The clay-rocks investigated in these studies, ranged from unconsolidated to indurated clays and shales, all characterised by small pores (2-100 nm) and very low hydraulic conductivity (K < 10-12 m·s-1) or permeability coefficients (k < 10-19 m²). Studies concerning radioactive waste disposal include investigations of both the natural host rock formation and synthetic/engineered backfill material at a depth of a few hundred meters (IAEA, 2003, 2009). Within a geological disposal facility, hydrogen is generated by anaerobic corrosion of metals and through radiolysis of water (Rodwell et al., 1999; Yu and Weetjens, 2009). Additionally, methane and carbon dioxide are generated by microbial degradation of organic wastes (Rodwell et al., 1999; Ortiz et al., 2002; Johnson, 2006; Yu and Weetjens, 2009). The focus of carbon capture and storage (CCS) studies is on the analysis of the long-term sealing efficiency of lithologies above depleted reservoirs or saline aquifers, typically at larger depths (hundreds to thousands of meters). During the last decade, several studies were published on the sealing integrity of clay-rocks to carbon dioxide (Hildenbrand et al., 2004; Li et al., 2005; Hangx et al., 2009; Harrington et al., 2009; Skurtveit et al., 2012; Amann-Hildenbrand et al., 2013). In the context of petroleum system analysis, a significant volume of research has been undertaken regarding gas/oil expulsion mechanisms from sources rocks during burial history (Tissot & Pellet, 1971; Appold & Nunn, 2002), secondary migration (Luo et al., 2008) and the capillary sealing capacity of caprocks overlying natural gas accumulations (Berg, 1975; Schowalter, 1979; Krooss, 1992; Schlömer and Kross, 2004; Li et al., 2005; Berne et al., 2010). Recently, more attention has been paid to investigations of the transport efficiency of shales in the context of oil/gas shale production (Bustin et al., 2008; Eseme et al., 2012; Amann-Hildenbrand et al., 2012; Ghanizadeh et al., 2013, 2014). Analysis of the migration mechanisms within partly unlithified strata becomes important when explaining the 3 origin of overpressure zones, sub-seafloor gas domes and gas seepages (Hovland & Judd, 1988; Boudreau, 2012). The conduction of experiments and data evaluation/interpretation requires a profound process understanding and a high level of experience. The acquisition and preparation of adequate samples for laboratory experiments usually constitutes a major challenge and may have serious impact on the representativeness of the experimental results. Information on the success/failure rate of the sample preparation procedure should therefore be provided. Sample specimens “surviving” this procedure are subjected to various experimental protocols to derive information on their gas transport properties. The present overview first presents the theoretical background of gas diffusion and advective flow, each followed by a literature review (sections 2 and 3). Different experimental methods are described in sections 4.1 and 4.2. Details are provided on selected experiments performed at the Belgian Nuclear Research Centre (SCK-CEN, Belgium), Ecole Centrale de Lille (France), British Geological Survey (UK), and at RWTH-Aachen University (Germany) (section 4.3). Experimental data are discussed with respect to different petrophysical parameters outlined above: i) gas diffusion, ii) evolution of gas breakthrough, iii) dilation-controlled flow, and iv) effective gas permeability after breakthrough. These experiments were conducted under different pressure and temperature conditions, depending on sample type, burial depth and research focus (e.g. radioactive waste disposal, natural gas exploration, or carbon dioxide storage). The interpretation of the experimental results can be difficult and sometimes a clear discrimination between different mechanisms (and the controlling parameters) is not possible. This holds, for instance, for gas breakthrough experiments where the observed transport can be interpreted as intermittent, continuous, capillary- or dilation-controlled flow. Also, low gas flow rates through samples on the length-scale of centimetres can be equally explained by effective two-phase flow or diffusion of dissolved gas

Ruxolitinib for Glucocorticoid-Refractory Acute Graft-versus-Host Disease

BACKGROUND: Acute graft-versus-host disease (GVHD) remains a major limitation of allogeneic stem-cell transplantation; not all patients have a response to standard glucocorticoid treatment. In a phase 2 trial, ruxolitinib, a selective Janus kinase (JAK1 and JAK2) inhibitor, showed potential efficacy in patients with glucocorticoid-refractory acute GVHD. METHODS: We conducted a multicenter, randomized, open-label, phase 3 trial comparing the efficacy and safety of oral ruxolitinib (10 mg twice daily) with the investigator's choice of therapy from a list of nine commonly used options (control) in patients 12 years of age or older who had glucocorticoid-refractory acute GVHD after allogeneic stem-cell transplantation. The primary end point was overall response (complete response or partial response) at day 28. The key secondary end point was durable overall response at day 56. RESULTS: A total of 309 patients underwent randomization; 154 patients were assigned to the ruxolitinib group and 155 to the control group. Overall response at day 28 was higher in the ruxolitinib group than in the control group (62% [96 patients] vs. 39% [61]; odds ratio, 2.64; 95% confidence interval [CI], 1.65 to 4.22; P<0.001). Durable overall response at day 56 was higher in the ruxolitinib group than in the control group (40% [61 patients] vs. 22% [34]; odds ratio, 2.38; 95% CI, 1.43 to 3.94; P<0.001). The estimated cumulative incidence of loss of response at 6 months was 10% in the ruxolitinib group and 39% in the control group. The median failure-free survival was considerably longer with ruxolitinib than with control (5.0 months vs. 1.0 month; hazard ratio for relapse or progression of hematologic disease, non-relapse-related death, or addition of new systemic therapy for acute GVHD, 0.46; 95% CI, 0.35 to 0.60). The median overall survival was 11.1 months in the ruxolitinib group and 6.5 months in the control group (hazard ratio for death, 0.83; 95% CI, 0.60 to 1.15). The most common adverse events up to day 28 were thrombocytopenia (in 50 of 152 patients [33%] in the ruxolitinib group and 27 of 150 [18%] in the control group), anemia (in 46 [30%] and 42 [28%], respectively), and cytomegalovirus infection (in 39 [26%] and 31 [21%]). CONCLUSIONS: Ruxolitinib therapy led to significant improvements in efficacy outcomes, with a higher incidence of thrombocytopenia, the most frequent toxic effect, than that observed with control therapy

Helmond’s of Bosau Pons Longissimus. Archaeological underwater excavations of the bridge constructions of the Slavic and early German olsborg stronghold on the Grosser Ploner Lake (north Germany)

The article is aimed at presentation of results of archaeological underwater excavations of remains of the early Medieval bridge on the stronghold island Oslborg. There are vestiges of the Slavic and early German stronghold on the Grosser Plòner Lake island near Plon in north Germany. This stronghold has been repeatedly mentioned by Adam of Bremen and Helmold of Bosau - the 11th and 12th century annalists. Underwater excavations, undertaken in two study zones of 75 square meters in total, resulted in discovery of the bridge remains which revealed themselves in the form of 228 posts being elements of its bearing construction placed on the lake bottom. Dendrochronological analysis of 79 posts indicates that the bridge was constructed in 975 AD and it was rebuilt many times afterwards. Trees for subsequent reconstructions were cut down in the years 994, 995, 1005, 1008, 1011, 1012, 1013, 1025 and for the last time in 1096 AD. The excavations revealed also an assemblage of Slavic and early German pottery as well as 56 artefacts including 14 spearheads and 6 axes. These military accessories can possibly be linked with the 1075, 1128 or 1139 war, mentioned by Helmold of Bosau

Helmolds von Bosaupons longissimus. Archaologische Unterwasserausgrabungen bei den Briickenanlagen neben der slawischen und frühdeutschen Burg Olsborg im Grossen Ploner See (Norddeutschland)

The article is aimed at presentation of results of archaeological underwater excavations of remains of the early Medieval bridge on the stronghold island Oslborg. There are vestiges of the Slavic and early German stronghold on the Grosser Plòner Lake island near Plon in north Germany. This stronghold has been repeatedly mentioned by Adam of Bremen and Helmold of Bosau - the 11th and 12th century annalists. Underwater excavations, undertaken in two study zones of 75 square meters in total, resulted in discovery of the bridge remains which revealed themselves in the form of 228 posts being elements of its bearing construction placed on the lake bottom. Dendrochronological analysis of 79 posts indicates that the bridge was constructed in 975 AD and it was rebuilt many times afterwards. Trees for subsequent reconstructions were cut down in the years 994, 995, 1005, 1008, 1011, 1012, 1013, 1025 and for the last time in 1096 AD. The excavations revealed also an assemblage of Slavic and early German pottery as well as 56 artefacts including 14 spearheads and 6 axes. These military accessories can possibly be linked with the 1075, 1128 or 1139 war, mentioned by Helmold of Bosau.The article is aimed at presentation of results of archaeological underwater excavations of remains of the early Medieval bridge on the stronghold island Oslborg. There are vestiges of the Slavic and early German stronghold on the Grosser Plòner Lake island near Plon in north Germany. This stronghold has been repeatedly mentioned by Adam of Bremen and Helmold of Bosau - the 11th and 12th century annalists. Underwater excavations, undertaken in two study zones of 75 square meters in total, resulted in discovery of the bridge remains which revealed themselves in the form of 228 posts being elements of its bearing construction placed on the lake bottom. Dendrochronological analysis of 79 posts indicates that the bridge was constructed in 975 AD and it was rebuilt many times afterwards. Trees for subsequent reconstructions were cut down in the years 994, 995, 1005, 1008, 1011, 1012, 1013, 1025 and for the last time in 1096 AD. The excavations revealed also an assemblage of Slavic and early German pottery as well as 56 artefacts including 14 spearheads and 6 axes. These military accessories can possibly be linked with the 1075, 1128 or 1139 war, mentioned by Helmold of Bosau.The article is aimed at presentation of results of archaeological underwater excavations of remains of the early Medieval bridge on the stronghold island Oslborg. There are vestiges of the Slavic and early German stronghold on the Grosser Plòner Lake island near Plon in north Germany. This stronghold has been repeatedly mentioned by Adam of Bremen and Helmold of Bosau - the 11th and 12th century annalists. Underwater excavations, undertaken in two study zones of 75 square meters in total, resulted in discovery of the bridge remains which revealed themselves in the form of 228 posts being elements of its bearing construction placed on the lake bottom. Dendrochronological analysis of 79 posts indicates that the bridge was constructed in 975 AD and it was rebuilt many times afterwards. Trees for subsequent reconstructions were cut down in the years 994, 995, 1005, 1008, 1011, 1012, 1013, 1025 and for the last time in 1096 AD. The excavations revealed also an assemblage of Slavic and early German pottery as well as 56 artefacts including 14 spearheads and 6 axes. These military accessories can possibly be linked with the 1075, 1128 or 1139 war, mentioned by Helmold of Bosau.Bleile R. 1999 Vorbericht zu unterwasserarchàologischen Untersuchungen an einer Slawischen Briickenanlage im PlauerSee bei Quetzin, Landkreis Parchim (Mecklenburg-Vorpommern), „Nachrichtenblatt Arbeitskreis Unterwasserarchaologie” Bd. 5, S. 32-35.Bleile R. 2003 Briicken unter Wasser. Neue Ergebnisse zu slawischen Briicken und Bohlenwegen in Mecklenburg-Vorpommern, „Mitteilungen der Deutschen Gesellschaft fur Archàologie des Mittelalters und der Neuzeit” 14, S. 80-84.Freytag H.J. 1985 Die Lage der slawischen und friihen deutschen Burg Plon, „Zeitschrift der Gesellschaft für Schleswig-holsteinische Geschichte” Bd. 10, S. 27-52.Hucke K. 1952 Wo lag die wendische Burg Plune?, „Die Heimat” Bd. 59, S. 136—139.Kempke T. 1992 Slawen in Ostholstein. Ausgrabungen in Bosau am Ploner See, (in:) Der Vergangenheit auf der Spur. Archàologische Siedlungsforschung in Schleswig-Holstein, Hrsg. M. Miiller-Wille und D. Hoffmann, S. 141-162.Kempke T. 1998 Archàologische Beitràge zur Grenze zwischen Sachsen und Slawen im 8.-9. Jahrhundert, (in:) Studien zur Archàologie des Ostsseeraumes. Von der Eisenzeit zum Mittelalter (Festschrift Michael Miiller-Wille), Hrsg. A. Wesse, Neumiinster, S. 373-382.Mittelstàdt U. 1976 Die Entwicklung der Stadi Plon bis zum Ausgang des Mittelalters, „Jahrbuch tur Heimatkunde im Kreis Plòn-Holstein” Jg. 7, S. 5-34.Kiefmann H.M. 1978 Historisch-geographische Untersuchungen zur alteren Kulturlandschafts-entwicklung, (in:) Bosau. Untersuchung einer Siedlungskammer in Ostholstein unter Leitung von Hermann Hinz, „Offa-Biicher” Bd. 38.Kola A., Wilke G. 2000 Briicken vor 1000 Jahren. Unterwasserarchaologie bei der polnischen Herrscherpfalz Ostrów Lednicki, Toruń.Krambeck H.J. 1979 A numercial-topographical model of Lake Grofier Plòner See and its application to the calculation of Seiches, „Archiv Hydrobiological” Bd. 87-3, S. 262-273.Wilke G. 1985 Most wczesnośredniowieczny z Bobęcina kolo Miastka. Wstępne wyniki archeologicznych badań podwodnych i analiz dendrochronologicznych jego reliktów [Sum.: The early mediewal ages bridge of Bobącin near Miastko. Preliminary results of archaeological underwater investigations and dendrochronological analyses of its remains], „Acta Universitatis Nicolai Copernici”, Archeologia 11, Archeologia Podwodna 2, S. 3-26.Wilke G. 1995 Lokalizacja stanowisk archeologicznych pod lustrem wody na przykładzie Jeziora Płońskiego Wielkiego (Grosser Ploner See) w północno-zachodnich Niemczech [Sum.: Location of archaeological sites under water - level on the example of Płońskie Wielkie Lake (Grosser Ploner See) in North Germany], (in:) Archeologia podwodna jezior Niżu Polskiego, Hrsg. A. Kola, Toruń, S. 71-90.Wilke G. 1998 Archàologie unter Wasser. Untersuchungen der slawischen Briicken in Lednica-See bei der Insel Ostrów Lednicki (Polen), (in:) Studien zur Archàologie des Ostseeraumes. Von der Eisenzeit zum Mittelalter (Festschrift Michael Müller-Wille), Hrsg. A. Wesse, Neumünster, S. 195-203.Wilke G. 2000a Analiza chronologiczno-przestrzenna struktur palowych i próba rekonstrukcji mostu [Sum.: Chronological - spatial analysis of pile structures and an attempt of bridge reconstruction], (in:) Wczesnośredniowieczne mosty przy Ostrowie Lednickim, t. 1 : Mosty traktu gnieźnieńskiego, Hrsg. Z. Kurnatowska, Lednica-Toruń, S. 57-71.Wilke G. 2000b Briicken und Brückenbau im óstlichen Mitteleuropa um 1000, (in:) Europas Mitte um 1000. Beitrage zur Geschichte, Kunst und Archàologie, Hrsg. A. Wieczorek, H.M. Hinz, Handbuch zur Ausstellung, Stuttgart, S. 142-145

Bericht über archäologische Untersuchungen der Unter wasserrelikte der frühgeschichtlichen "Poznań-Brücke" (Rybitwy, Fst. 3a) im Lednica-See in den Jahren 1986 - 1987

Zwecks der Ausführung des langfristigen Programms der Forschungen über Wasserverkehrseinrichtungen in westslawischen Ländern im Mittelalter wurden im Jahre 1982 von der Arbeitsstelle für Unterwasserarchäologie an der Mikołaj-Kopernik-Universität in Toruń die archäologischen Unterwasseruntersuchungen der Brückenreste im Lednica-See angestellt. In den Jahren 1986 - 1987 konzentrierten sie sich auf die sog. „Poznań”-Brücke. Ihre Reste befinden sich an der westlichen Seite der Insel Ostrów Lednicki in Seetiefe bis 12 m, in einer Gesamtlänge von fast 440 m. Diese Untersuchungen wurden im Rahmen des interdisziplinären wissenschaftlichen Programms geführt, das sich auf den mittelalterlichen Siedlungskomplex auf Ostrów Lednicki konzentrierte. D ie Untersuchungen wurden vom Museum der Ersten Piasten auf der Insel Lednica inspiriert und koordiniert. Die Unterwasserarbeiten hatten die Verifizierung und zugleich die Fortsetzung der in den Jahren 1959 - 1961 im Lednica-See geführten Untersuchungen zum Ziel. Der einleitende Charakter dieser Vorarbeiten und die damit verbundenen Schluβfolgerungen und Hypothesen wie auch Zweifel darüber, das Objekt aufgrund der Analyse stratigraphischer Anordnung und chronologisch wenig empfindlicher Quellenmaterialien rekonstruieren und genau datieren zu können, trugen dazu bei, daβ die weiteren Forschungen erforderlich waren. Die Unterwasserarbeiten dauerten vom 25. Juni bis zum 28. Juli 1986 und vom 31. Mai bis zum 26. Juni 1987. Bei entsprechenden Explorations- und dokumentarischen Verfahren wurden die schon früher während der Untersuchungen der sog. „Gniezno”-Brücke benutzten Gittermeβgeräte und Schutzgitter angewandt. In der ersten Arbeitssaison wurden nur zwei kleine Gittermeβgeräte mit Maßen 4 x 8 m, die in zwei Untersuchungseinheiten mit Maßen 4 x 4 m geteilt wurden, wie auch das Schutzgitter mit Maßen 4 x 4 m benutzt. In der zweiten Arbeitssaison wurde auch ein anderes Gittermeβgerät mit Maßen 8 x 12 m, das in sechs Untersuchungseinheiten mit denselben Maβen, d.h. 4 x 4 m, geteilt wurde, angewandt. Die Anwendung der Schutzgitter und zwei Typen von Gittermeβgeräten ermöglichte, auf der Linie der Hauptmeβmagistrale die Untersuchungsgrundteile mit Maßen 4 x 4 m auszustecken. Wegen des großen Verbreitungsgebiets der Trümmer wurde die Untersuchung der Brücke in fünf Grundteilen in jedem Streifen vorgenommen, die von 1 bis 5 arabisch beziffert wurden. Die Unterwasserforschungen im Jahre 1986 betrafen insgesamt 9 Grundteile mit Gesamtfläche von 144 m2 (Grundteile 1 - 5 , Streifen VI, 20 bis 24 m vom Nullpunkt der Magistrale; Grundteile 1 - 4 , Streifen VII, 24 bis 28 m von der Magistrale). Die Untersuchungen im Jahre 1987 betrafen in demselben Umkreis 8 Grundteile mit Fläche von 128 m2 (Grundteile 2 - 4, Streifen V, 16 bis 20 m von der Magistrale; Grundteil 5, Streifen VII, 24 bis 28 m; Grundteile 2 - 5 , Streifen VIII, 28 bis 32 m von der Magistrale). Die Untersuchungen betrafen auch 3 Grundteile im Streifen XVI und XVII (Grundteile 2 - 3, Streifen XVI, 60 bis 64 m von der Magistrale; Grundteil 2, Streifen XVII, 64 bis 68 m). Der Bodensatz wurde, je nach seiner Lage, von der Dicke 40 - 100 cm exploriert. Mittels einer Saugsthralpumpe wurde aus dem Seegrund ca. 150- 170 m3 Fördergut in Form von wässerigem Schlamm, feinkörnigem Sand, grobdetriter Ghytia wie auch zahlreichen kleinen Steinen, Muscheln und Holzspänen gewonnen. Infolge der Exploration der Aufschichtungen von Grundanschwemmungen wurden in der Länge von 12 m (das 16. bis 28. Meter der Hauptmagistrale) die Brückenreste aufgedeckt. Es waren senkrecht, meistens aber schräg in den Seegrund eingeschlagene Pfähle und einige horizontale Elemente der einstigen Überwasserbrückenkonstruktion, die auf dem Seegrund durcheinanderliegende Trümmer bildeten. Die planigraphische Analyse der 64 Pfähle der Tragkonstruktion des untersuchten Objekts läβt feststellen, daβ sie hauptsächlich in zwei Reihen auftraten. Sie waren jedoch weder in der Breite (Abstand der Tragpfeiler) noch in der Länge einzelner Abschnitte (Abstand der Brückenjoche) regelmäßig, bestimmten Modulen entsprechend angeordnet, sondern bildeten zwei ziemlich breite (manchmal bis 5 m) Streifen. Aufgrund dessen ist es schwer festzustellen, welche Breite die untersuchte Brücke ursprünglich hatte. Zur Zeit ist es auch schwierig, die Dimensionen des Objekts zu bestimmen und sie zu rekonstruieren, was 1961 ohne genügende Quellenbasis die Verfasser der Veröffentlichung der Unterwasserforschungsergebnisse getan haben. Was die Konstruktion der „Poznań“-Brücke anbetrifft, kann man heute nur annehmen, daβ das Grundelement des Brückenjoches zwei aus einigen Pfählen bestehende Pfeilerbündel bildeten, die über dem Wasserspiegel mit einer Querkonstruktion zusammengebunden waren. Die mit Längskonstruktionen verbundenen einzelnen Brückenjoche bildeten erst die Grundlage der monolithischen Brückenkonstruktion. Die Ergebnisse der dendrochronologischen Analyse lassen die untersuchte Brücke in das 11. Jh. datieren. Die zwei Jahre dauernden Untersuchungen der „Poznań”-Brückenreste brachten außer dem keramischen Material — darunter gewisse Anzahl von fast gänzlich erhalten gebliebenen Gefäβen — auch 64 Funde aus Holz, Eisen, Geweih, Knochen, Leder, Stein und Blei