This sejm was convened on 6 December 1648. The pre-sejm sejmiks were held from the end of November 1648 till the beginning of January 1649. The sejm sessions began on 19 January 1649, after a coronation of John II Casimir, that took place two days before (17 January 1649). Franciszek Dubrawski, chamberlain of Przemyśl, was elected the marshal. The proceedings, often quite turbulent and eventful, were held under the shadow of the Cossack rebellion (Khmelnytsky Uprising), especially because

The sejm was called by king Sigismund I on 11 September 1539 to be held on 6 January 1540 in Piotrków. The pre-sejm sejmiks were held in October of 1539. The sejm should have begun on Epiphany (6 January 1540) but in fact the sessions started on 19 January 1540. The main roles during the proceedings were played by king Sigismund II Augustus and queen Bona Sforza. The deputies submitted to the king a list of demands: appointing the vacant seat of hetman office, closing the