It is one of a very few cities which was actually planned in the Middle Ages. Founded in the second half of the 12th century by Jutta Claricia, Landgravine of Thuringia and sister of Emperor Frederick I, it got market rights in 1198 and city rights in 1265. Due to the excellent strategic lay between two lakes, which are emponymous for the city, and a ridge of hills it became quickly a very important trade centre, especially for fish and woad. Some notabilities lived on the Runneburg and in 1446 William III, Duke of Luxembourg adopted the first thuringian constitution. In time of Renaissance it became less importend and the two lakes were drained. But after the Congress of Vienna it was awarded by Prussia and got a revival as district capital.
Today, Weißensee is famous for its medieval castle, one of the largest in Thuringia, and for its annual Bierfest.