Before the Deluge. The extraordinary sejm in Warsaw. 1655.
The sejm was convened by the king John II Casimir in April 1655. The pre-sejm sejmiks were held in the same month. The rush to convene the sejm was the result of the Swedish invasion threat (besides, the war against Russia was already on). Jan Kazimierz Umiastowski was elected the marshal of the Chamber of Deputies. Sejm focused on the state defence matters, securing the Greater Poland and Podolia. The general levy was announced, the artillery and piechota łanowa [form of infantry, drafted on the basis of an old Polish field measurement “łan”, amounting from ca. 18 to 28 hectares] were reformed. The strongholds in Poznań, Lviv and Kamieniec were reinforced. The execution of overdue taxes was also adopted, as well as the new taxes. The sejm finished proceedings on 20 June 1655.
See: W. Czapliński, Sejm w latach 1587-1696 [Sejm in period 1587-1696], in: Historia sejmu polskiego [The history of Polish sejm], t. 1, Warszawa 1984, red. J. Michalski, s. 217-299. E. Opaliński, Sejm srebrnego wieku 1587-1652. Między głosowaniem większościowym a liberum veto [Sejm of the Silver Age 1587-1652. Betwixt majority voting and liberum veto] , Warszawa 2001; S. Ochmann-Staniszewska, Z. Staniszewski, Sejm Rzeczypospolitej za panowania Jana Kazimierza Wazy. Prawo-doktryna-praktyka, [Sejms of the Commonwealth under the rule of John II Casimir Vasa. Law-doctrine-practice] T. 1, Wrocław 2000, s. 233-252. H. Olszewski, Sejm Rzeczypospolitej epoki oligarchii (1652-1763). Prawo-praktyka-teoria-programy [Sejm of the Commonwealth in the oligarchy era (1652-1763). Law-practice-theory-programs], Poznań 1966;3, Poznań 1966). Ustawodawstwo zob. Volumina Constitutionum, T. 4, cz. 1, Design and layout prepared by S. Grodziski, Marcin Kwiecień, K. Fokt, Foreword W. Uruszczak, Warszawa 2015, s. 346-374.