Casimir I the Restorer
He was the third son of Casimir I the Restorer by his wife Maria Dobroniega, daughter of Vladimir the Great, Grand Duke of Kiev. He was named after his paternal grandfather, Mieszko II Lambert. He had three brothers: Bolesław II Szczodry, Władysław Herman and Otto. His sister was Świętosława Swatawa, later queen of Czech.