Mieszko II Lambert

Mieszko II Lambert (ca. 990 - May 10, 1034) was a king of Poland from 1025 to 1031, and a duke of Poland from 1032 to 1034 from the Piast dynasty. He was the second son of Boleslaw I the Brave. He is the third known Polish ruler. He was father of Casimir I.
He was probably named after Mieszko I of Poland, who was his grandfather.
In 1028 and in 1030 he attacked Saxony. Later, Poland was attacked by Germany, Bohemia, and Kiev. When Poland was attacked by Yaroslav the Wise in 1031, Mieszko lost control over Poland.