Wenceslaus I tried to lead a policy of approaching to Poland, despite his still existing ties with the Bohemian Kingdom (he was formally a vassal of Bohemia). In 1448, Wenceslaus I promised to support the Polish efforts to defend the country's frontiers. Five years later, he and his brother Jan IV privately gave their military services to the king. The informal relationship between the Duke of Zator and the Polish crown was confirmed in 1456 when Wenceslaus I paid homage to King Casimir IV. This step was made public only in 1462 in the Congress of Głogów. Wenceslaus I's exact date of death is unknown, but is generally ranked between 1465 and before 29 July 1468. His place of burial is also unknown, but presumably was in the Church of Saint Adalbert and Saint George in Zator. Marriage and issue Around 1450 Wenceslaus married with Małgorzata (d. aft. 1468), daughter of Urban Kopczowski called Świrczyna, a noblemen from the Duchy of Siewierz. This information was provided by the chronicler Jan Długosz. Some historians based on Długosz with no reason wrote that her name was Maria. Urban was probably the same person as Urban of Kopczowice (Urban z Kopczowic), mentioned in document form 1457. According to the chronicler Jan Długosz, this non-dynastic marriage was concluded for love, in an extraordinary exception between the Silesian Dukes and the House of Piast in general. They had seven children: Casimir II (b. ca. 1450 – d. 8 January/7 July 1490) Wenceslaus II (b. ca. 1450/55 – d. bef. 5 October 1487) Jan V (b. bef. 1455 – d. 17 September 1513) Władysław (b. 1455 – d. by 28 May/21 September 1494) Sophie (d. ca. 1466) Katharina (d. ca. 1466) Agnes (d. aft. 21 October 1465). Ancestry References 1410s births 1460s deaths Piast dynasty