January 1426 in history

Died in January 1426

Jan 21 Siemowit IV Duke of Masovia one of the Dukes of Masovia of the old Polish Piast royal family. His domain included the lands of Czersk, Rawa, Sochaczew, Płock and Gostynin. In 1381 he inherited Wisz and in 1387 Bełz