Drawn in 1652 by Johann Gregor Memhardt, and thus known as the Mamhardt Plan, this is the earliest known map of Berlin. Menhardt prepared this plan while employed by Frederick William, the Great Elector, to restore and rebuild the royal residences in and around Berlin following the devastation of the Thirty Year War, in which much of Berlin was destroyed and nearly half of its population lost. Oriented to the east and centered on the Spree River, Memhardt's map covers mediaeval Berlin, Colln, and the Castle District. It is the only surviving document to illustrate Berlin's medieval walls. Important buildings are rendered in profile and include the royal residence, several churches, the Mühlendamm, and the 'Olde Markt.' THis map was prepared in 1652 to illustrate Merian's Topographia Electorat, Brandenburgici et Ducatus Pomeraniae.