The Ukranen (also: Ukrer ) include not only Retschanen ( Slavic reka river ) to the West Slavic tribes. Their name is derived from the river Ucker.
Around the 7th century Slavs migrated into the Uckergebiet, after which they were referred to as Ukranen. This area was first documented mention as terra ukera and called only from the 15th century as Uckermark. Center of the tribe was the Uckerseen top and Unteruckersee. 948, the area was the bishopric of Brandenburg instructed to mission. During the Slavs uprising 983, the area belonged to Lutizenbund.