The earliest evidence of settlements in the area of today’s Berlin are a wooden beam dated from approximately and leftovers of wooden houseparts dated to digging in Berlin Mitte.The first written records of towns in the area of present-day Berlin date from the late 12th century. Spandau is first mentioned in and Köpenick in, although these areas did not join Berlin until. The central part of Berlin can be traced back to two towns. Cölln on the Fischerinsel is first mentioned in a document, and Berlin, across the Spree in what is now called the Nikolaiviertel, is referenced in a document from. The former is considered to be the founding date of the city. The two towns over time formed close economic and social ties and eventually merged in 1307 and came to be known as Berlin.