Bolesław II of Masovia

Bolesław II (c. 1253–1313), younger son of Siemowit I of Masovia, ruled Masovia with his brother Konrad II after 1262 and received Płock in 1275. In 1279 he married Sophia.

After Leszek II the Black died in 1288 he seized Kraków and Sandomierz and claimed the senioral throne, but withdrew after the Battle of Siewierz in 1289. On Konrad II's death in 1294 he reunited all Masovia, later promoted Warsaw, and in 1310 enfeoffed his sons with Warsaw and Czersk.