Siemomysl is the third legendary Polish duke, and said to be the father of Poland's first historical ruler, Mieszko I. Siemomysl is credited with leaving the lands known as Greater Poland to his son, who further expanded them during his reign.

http://genealogy.euweb.cz/piast/piast1.html

The Piast family

Ziemomysl, Ct of Poland (922-962), +ca 962/963 (possibly a son of Leszek); He had issue:

A1. son, +963
A2. Czcibór, +after 24.6.972
A3. Mieszko I, baptized in 966, Ct of Poland (962-993), *922, +Poznan 25.5.992, bur St.Peter, Poznan; 1m: NN; 2m: 965 Dobrava of Bohemia (*ca 937 +977); 3m: 979/980 Oda (+1023) dau.of Gf Dietrich von Haldensleben, Mgve of the Nordmark
...
A4. Adleta, +after 997; 1m: Mihály Arpád (+ca 978); 2m: ca 980 Geza of Hungary (+1.2.997)

Ziemomysl

tytul - ksiaze polski urodzony - okolo 900 r. zmarl - przed 963 r. dynastia - Piastowie herb - Orzel Piastowski

Rodzice :

ojciec - Leszek matka - NN
Rodzina

1 . zona - (kilka zon poganek) od : X w. Potomstwo z tego zwiazku 1 . syn - Mieszko I 2 . syn - Prokuj 3 . syn - Czcibór 4 . córka - Adelajda

913-963 talet

Barn:
Mieszko I, född cirka 930, död 992-05-25