On 11 June 1441 Catherine married Elector Frederick II of Brandenburg (1413–1471) in Wittenberg.

Frederick had earlier asked for Catherine's hand unsuccessfully.

The promise of marriage was finally made as part of a contract that settled the conflict between Brandenburg and Saxony over the ownership of Lusatia and sealed an alliance between the two countries.

Frederick had numerous affairs, and his son Erasmus was born out of wedlock.

Catherine had three children with Frederick: This article about a member of the German nobility is a stub.