Casimir also signed an alliance with Yaroslav I the Wise, the Prince of Kievan Rus', who was sealed by Casimir's marriage with Yaroslav's sister, Maria Dobronega.
Casimir also signed an alliance with Yaroslav I the Wise. The Prince of Kievan Rus'was the Wise. Kievan Rus' was sealed by Casimir's marriage with Yaroslav's sister. Yaroslav's sister was Maria Dobronega.