Siemomysł (died c. 950–960) was the third pagan Polans duke of the Piast dynasty, and the father of Poland's first historical ruler, Mieszko I. He was listed by Gallus Anonymous in his Gesta principum Polonorum and was the son of Lestek, the second known Duke of the Polans. According to Gallus' account and historical research, Siemomysł has been credited with leaving the lands of Polans, Goplans and Masovians to his son Mieszko I, who further expanded them during his reign.
His name in German was Ziemomysl. . According to Henryk Łowmiański he aided the Ukrani uprising against the Germans in 954 AD.
See also 
- ^ K. Jasiński, Siemomysł, Polski Słownik Biograficzny, vol.. 37, 1996, p. 58-59.
- ^ Lukowski, Jerzy; Hubert Zawadzki (2006). A Concise History of Poland. Cambridge University Press. pp. 3–4. ISBN 978-0-521-61857-1.