A major turning point in the development of the Amstel river mouth is the All Saint's Flood of 1170. In an extremely short period of time, the shallow river IJ turned into a wide estuary, which from then on offered the Amstel an open connection to the Zuiderzee, IJssel and waterways further afield. This made the water flow of the Amstel more active, so excess water could be drained better. With drier banks, the downstream Amstel mouth became attractive for permanent habitation. Moreover, the river had grown from an insignificant peat stream into a junction of international waterways. A settlement was built here immediately after the landscape change of 1170, and right from the start of its foundation it focused on traffic, production and trade; not on farming, as opposed to how communities had lived further upstream for the past 200 years and northward for thousands of years. The construction of a dam at the mouth of the Amstel, eponymously named Dam, is historically estimated to have occurred between 1264 and 1275. The settlement first appeared in a document concerning a road toll granted by the count of Holland Floris V to the residents ''apud Amestelledamme'' 'at the dam in the Amstel' or 'at the dam of Amstelland'. This allowed the inhabitants of the village to travel freely through the County of Holland, paying no tolls at bridges, locks and dams. By 1327, the name had developed into ''Aemsterdam''.