Cölln This article is about Cölln on an island of the Spree . Cölln is also an old spelling for Köln on the Rhine , for this city see Cologne . Originally Cölln was the sister town of old Berlin located on the southern Spree Island in Germany 's Mark Brandenburg of the 13th century . Today this twin city zone is located in the center of modern Berlin in the vicinity of the Museum Island , then called Fisher 's Island or Spree Island . Cölln is first mentioned in writing in 1237 , Berlin in 1244 . The two towns were separated only by the river Spree , hence there was a close connection right from the start . Since the trade road from Magdeburg to the East crosses the twin town the inland water-transportation routes also passed through the town , Cölln/Berlin quickly came to prosperity . A common policy of Berlin and Cölln led 1308 to a first alliance with other towns in the Mark ( Brandenburg an der Havel , Frankfurt ( Oder ) and Salzwedel ) to defend their rights against the sovereign . The Elector Frederick II ended the autonomy of Cölln/Berlin and declared the twin town to his residence in 1451 . In 1709 the twin cities Cölln and old Berlin merged to form a single city which was the base of today 's Berlin . As old Berlin was twice as big as Cölln at that time , the merged city was named Berlin . The name survives in the Berlin suburb of Neukölln ( New Cölln ) , which was originally a southern extension of Cölln , as well as in the park `` Köllnischer Park '' and the street `` Am Köllnischen Park '' , both located in the area of the ancient town . An outdoor enclosure , situated directly in the park , is home of three brown bears ( the bear is the heraldic animal of the City of Berlin ) , representing the cradle of the city . Categories : History of Berlin In other languages : Deutsch | Nederlands | Plattdüütsch 