Brzeg was one of the capitals of Piast Silesia and one of the four most important medieval centres in the province. The history of the town and its historical cartography provide a wealth of information on the mills, the river harbour and the bridge crossing. The choice of the location of the town was related to the shape of the riverbed, which made it easy to build a bridge.
The example of Wrocław, with its wide Oder riverbed divided into many narrow branches, is significant. The Oder was not only an opportunity for the city, but also a threat due to floods. Wrocław had to be protected by numerous embankments, which conditioned the creation of communication routes as early as in the Middle Ages, but which were only best recorded by cartography from the end of the eighteenth century.
Milicz was situated on the northern border of Silesia, whose boundary was the Barycz River. Historical cartography shows the extraordinary importance of the river and the surrounding ponds (temporarily filled with water) for the town’s shape. The course of the river, as historical cartography confirms, is also important in cases where we would not expect it, such as Wiązów, situated on the Oława River. The town was built on a riverside escarpment, and the steepness of its slope directly influenced the shape of the town’s designated plots, as well as the form of the partially preserved bastion from the modern period.
The enormous effort made by cartographers to produce maps and plans illustrating these environmental elements and their changes perfectly confirms the importance of this natural factor of urbanisation. In the face of the new ecological challenges, this issue still seems relevant.