Konrad II of Masovia

Konrad II of Czersk (pl: Konrad II czerski; c. 1250 – 24 June 24/21 October 1294), was a Polish prince member of the House of Piast, Duke of Masovia during 1264-1275 jointly with his brother, since 1275 sole ruler over Czersk and Duke of Sandomierz during 1289.

He was the eldest son of Siemowit I of Masovia and Pereyaslava, a daughter of Prince Daniel of Halych.

Konrad II is mentionet for the first time in 1262, when Lithuanian Grand Duke Treniota launched a major campaign against Masovia. He and his father stayed at a small fort in Jazdów when they were surprised by the attack; Siemowit I was killed during the battle and Konrad II was captured by the Lithuanians.

With Konrad II as a prisoner of the Lithuanians and his brother Bolesław II too young to rule, the regency of the Duchy of Masovia was exercised by Bolesław the Pious and the children's mother Pereyaslava. After two years of captivity, Konrad II was released and recover his lands left to him by his father.

In terms of foreign policy, Konrad II continued the line of his father, working closely with Bolesław V the Chaste, Leszek II the Black and Bolesław the Pious. He fought alongside Hungary in the war which opposed Bohemia for the Babenberg inheritance. In 1271 became part of a coalition against Henryk IV Probus, to prevent it from providing support to the Bohemian King Ottokar II. Two years later, the same coalition attacked Władysław Opolski who during the general confusion for the Bohemian-Hungarian war, tried to obtain the Seniorate from Bolesław V, but without results.

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