Duchy of Kopanica

Jaxa of Köpenick
Polish painting of Jaxa, made in Krakow in 1757
Born	12th century
Died	12th or 13th century

Jaxa of Köpenick (sometimes Jaksa or Jacza of Copnic, Polish: Jaksa z Kopnika or Jaksa z Kopanicy, Jaksa being an early Sorbian and/or Polish form of James) (fl. 1151-1157) was a prince of the West Slavic Sprevani. He was an opponent of Albert the Bear during the formation of Brandenburg in 1157.

Jaxa, a prince of the Slavic Sprevani in Köpenick (present day borough of Berlin) was probably a relative of the Hevelli (Stodoran) prince Pribislav and as a result had a claim to rule over the Stodrans after Pribislav's death. Unbeknownst to Jaxa and most of the Stodoran nobility, Pribislav, around 1140, had made an agreement with Albert the Bear, bequeathing the lands of the Stodorans to the latter. Pribislav died in 1150, and his widow sent for Albert. In the meantime she hid the duke's corpse, afraid that if the testament became known before Albert took control of Brenna (Brandenburg) a general rebellion would break out. However Albert was delayed, and the stench of the decomposing corpse gave away his death. The nobility of the Stodorans deliberated as to their next step, while Jaxa was also informed. Albert arrived first and took control of Brenna, with Jaxa showing up shortly afterward on the same day. The circumstances of the transfer of power in Brenna, and the duplicity of Pribislav's widow in the end did provoke a Slavic uprising (although many German peasants joined) against German rule.

The region of Köpenick and Brenna stood astride the main land routes from west of the Oder into the Kingdom of Poland. For this reason who controlled these lands was of central importance to Polish rulers. Hence, Mieszko the Old, Duke of Greater Poland (later High Duke of Poland) actively supported Jaxa and the Slavic rebellion, fully aware that as long as German nobles were busy fighting Slavs to the west, they could not intervene into Polish affairs. Other Polish regional dukes also sent armed contingents to support Jaxa.