The formal marriage between Constance and Conrad took place in the border town of Santok in 1260, after the death of Przemysł I.
[2] Constance's dowry was the castellany of Santok, though without the main city, which remained in Greater Poland, given to the Margraviate of Brandenburg with the consent of a wiec reunited in Greater Poland, which took place on 1 July of that year in Poznań.
During her marriage, Constance bore her husband four children, three sons (John IV, Otto VII and Waldemar) and a daughter (Agnes, later wife of Albert I, Prince of Anhalt-Zerbst).
The war was fought intermittently and ended only in 1278, when Greater Poland recovered all of its lost domains.
[5] Her husband never remarried and died in 1304; Constance's only descendants were from her daughter Agnes, Princess of Anhalt-Zerbst: through her, she was one of the ancestors of Catherine II the Great of Russia.