During five weeks in June and July 2001 a small supplementaryexcavation was carried out at the Ag. AikateriniSquare. The purpose of the excavation was to clarify someproblems and test some ideas before the final publicationof the forthcoming volumes of the Greek–SwedishExcavations (GSE). For the Late Minoan IIIA:2/IIIB:1 period there was a question about the supposednorth-western wall of Building 1, Space G.3 It was thereforedecided to open a new trench (Trench 33) within thearea 508‑510/709.5‑714 (Fig. 1) – a trench which wouldpossibly also reveal further information on the two LM Idestructions noted in House IV of the LM I period. Forthe LM I period there were three more objectives: (a) tofind out whether House I, Room K (Fig. 1) incorporateda lustral basin in an earlier phase; (b) to investigate extensivelythe drainage system of the excavated buildingsand their connection to the “public” drain running in thestreet between Houses I and II; and (c) to investigate thestratified remains from the MM and EM periods still leftin the baulk between trenches 1 and 2 and 2 and 4, whichwere excavated in 1970. But in opening two new areas importantsupplementary information was revealed, relatedto periods which were not directly under investigation.Here follows a presentation of the 2001 excavation, periodby period from surface to bedrock