Sejm in collapse. The extraordinary Sejm in Grodno. 1729.
The Sejm was convened in June 1729, and local assemblies preceded it in July. The Sejm session began on 22 August, but, as early as 29 August, even before the election of the Marshal, it was disrupted by the veto of Jan Antoni Horain.
See: W. Konopczyński, Dzieje Polski nowożytnej (History of Modern Poland), vol. 2, Warsaw 1986.