Siemowit I of Masovia

Siemowit I of Masovia (Polish: Siemowit (Ziemowit) I mazowiecki) (d. 23 June 1262), was a Polish prince member of the House of Piast, Duke of Czersk during 1247-1248, Duke of Masovia (except Dobrzyń) during 1248-1262, ruler over Sieradz during 1259-1260. He was the sixth son of Konrad I of Masovia and his wife Agafia of Rus.

Siemowit I of Masovia

Siemowit I of Masovia (Polish: Siemowit (Ziemowit) I mazowiecki) (d. 23 June 1262), was a Polish prince member of the House of Piast, Duke of Czersk during 1247-1248, Duke of Masovia (except Dobrzyń) during 1248-1262, ruler over Sieradz during 1259-1260. He was the sixth son of Konrad I of Masovia and his wife Agafia of Rus.