This paper introduces the MICOLL Map, a digital historical map which is currently under construction by the ERC-funded project MICOLL: Migrating Commercial Law and Language: Rethinking Lex Mercatoria (11th-17th Centuries). The eventual aim of the map is to display the changing routes by which goods and information circulated in the late Middle Ages and the early modern period, with an initial focus on Northern Italy, Southern Germany, and Trans-Alpine exchange. The paper will firstly survey existing digital historical mapping tools before explaining how the MICOLL Map aims to go beyond the current state of the art in a number of ways, chiefly through the promotion of source transparency which will enable the map to be used as a source by professional historians. The second half of the paper will outline the current technical solutions in place to achieve this