Альбрехт Медведь
Jaxa of Köpenick (sometimes "Jaksa" or "Jacza of Copnic", , Jaksa being an early Sorbian and/or Polish form of "James") (fl. 1151–1157) was a prince of the West Slavic Sprevan Duchy of Kopanica. He was an opponent of Albert the Bear during the formation of Brandenburg in 1157.