Voivodeship in 1731. After August II's death in 1733, he rekindled his old ties with Leszczyński, but made some attempts to secure his own election to the throne. Eventually, however, he decided to grant Leszczyński his full support, doing so during the convocation sejm of 1733. He again served as Leszczyński's diplomat during the following War of the Polish Succession. In 1734, he switched sides and joined the supported Augustus III. After several years of distrust, August III started treating Poniatowski as one of his major advisers. Over the next few years, throughout the 1740s, he and familiar supported plans for reform and strengthening the Commonwealth, however most of them have failed due to liberum veto disrupting the Sejm proceedings. Those failures likely resulted in his apathy, and he became much less active on the political scene in the 1750s. On 6 June 1752 he received the office of castellan of Kraków. Near the end of his life, Poniatowski was among the richest magnates in the Commonwealth, with the value of his estates estimated at about 4 million zlotys. He died in Ryki on 29 August 1762, shortly after suffering a serious fall while walking. Family He was the son of Franciszek Poniatowski (1640/16501691–1695), łowczy podlaski in 1680 and cześnik wyszogrodzki in 1690, and his wife Helena Niewiarowska, who he had married in 1673 or 1674. His older brother Józef Poniatowski (1674after 1731) was a generał wojsk koronnych and married Helena Otfinowska, without issue. His younger siblings were Michał Jacenty Poniatowski, a Dominican, and Zofia Agnieszka Poniatowska, a Carmelitan Abbess in Kraków. He married firstly shortly after 1701 and divorced Teresa Woynianka-Jasieniecka, who died after 1710, without issue, and secondly Princess Konstancja Czartoryska on 14 September 1720. They had eight children. He was the father of: Kazimierz Poniatowski (15 September 1721 – 13 April 1800), podkomorzy wielki koronny between 1742 and 1773 and generał wojsk koronnych, who was created a Prince on 4 December 1764 and married on 21 January 1751 Apolonia Ustrzycka (17 January 1736 - 1814) and had issue Franciszek Poniatowski (1723 – 1749/1759), canon and provost in the Cathedral of Kraków (kanonik i proboszcz katedralny krakowski), chancellor of Gniezno in 1748 Aleksander Poniatowski (1725 – killed in action on 29 June 1744), adiutant of Karl von Lothringen Ludwika Maria Poniatowska (30 November 1728 – 10 February 1781), who married in 1745 Jan Jakub Zamoyski (? - 10