In the historiography of town planning, one still finds the old idea that the straight street is typical for the Renaissance, whereas medieval streets would typically be curved or crooked and irregular. In this article, this idea will be contested with the evidence of the scarce written sources concerning the subject of the layout of the city street from the twelfth to sixteenth centuries and of the urban form of the new towns that were built in that period. It will also be shown that traditional interpretations of the famous passage from Alberti’s De re aedificatoria, which describes the advantages of winding streets as compared to straight streets, are largely wrong. Moreover, it will be argued that the general idea of medieval town building as something completely different than Renaissance town building is not correct.