Oda of Haldensleben wife "Ote" and her sons by him (Mieszko and Lambert are only named; probably Świętopełk was already dead by that time or was in Pomerania as a ruler, according to modern historians). Mieszko I's oldest son, Bolesław I the Brave, is not mentioned, perhaps because he already received his inheritance (probably Lesser Poland, who included Kraków and some other cities). It's also believed that the document was inspired by Oda, who wanted to secure the inheritance of her sons (with the Papal protection) in detriment of her stepson Bolesław I. After the death of Mieszko I (25 May 992), Bolesław
Mieszko Kazimierzowic no mention of Mieszko's influence on Polish politics. Mieszko died on 28 January 1065. Year of death was noted by "Rocznik kapituły krakowskiej", while day by "Necrologium monasterii superioris Ratisbonensis". He died unmarried and childless. Mieszko Kazimierzowic Mieszko Kazimierzowic ("Kazimierzowic" means "son of Kazimierz") (16 April 1045 – 28 January 1065) was a Polish prince member of the House of Piast. According to some scholars, he was probably Duke of Kuyavia since 1058 until his death. He was the third son of Casimir I the Restorer by his wife Maria Dobroniega, daughter of Vladimir the Great, Grand Duke of Kiev.