titles than those found in rest of the world (see officials of the Polish–Lithuanian Commonwealth); the gist of the conflict, which took much of the Sejm's time around 1638–41, revolved around whether old prince titles (awarded to families before their lands were incorporated into the Commonwealth in the 1569 Union of Lublin), and the new titles, awarded more recently by some foreign courts, should be recognized. Wiśniowiecki was one of the chief participants in this debate, successfully defending the old titles, including that of his own family, and succeeding in abolishing the new titles, which gained him the enmity of another powerful magnate, Jerzy Ossoliński. Other than this conflict, in his years as a deputy (1635–46), Jeremi wasn't involved in any major political issues, and only twice (in 1640 and 1642) he served in the minor function of a commissar for investigating the eastern and southern border disputes. In 1637 Wiśniowiecki might have fought under Hetman Mikołaj Potocki against the Cossack rebellion of Pavel Pavluk (the Pawluk Uprising); Jan Widacki notes that historians are not certain whether he did and in either case, no detailed accounts of his possible participation survive. A year later, returning from the Sejm and from the engagement ceremony with Gryzelda, he gathered a 4,000 strong division that participated in putting down of the Ostrzanin Uprising and arrived at the region affected by the unrest in June that year. Together with Hetman Potocki he defeated the insurgents at the Battle of Żownin, which turned into a rather difficult siege of the Cossack camp that lasted from 13 June till the Cossack relief forces were defeated on 4 August, and the Cossacks capitulated on 7 August. Final years In 1641, after the death of his uncle Konstanty Wiśniowiecki, Jeremi became the last adult male of the Wiśniowiecki family and inherited all the remaining estates of the clan, despite a brief conflict with Aleksander Ludwik Radziwiłł who also claimed the inherited land. The conflict stemmed from the fact that Konstanty asked Jeremi to take care of his grandchildren, but their mother, Katarzyna Eugenia Tyszkiewicz, married Aleksander, who declared he is able and willing to take care of her children – and their estates. A year later, Katarzyna Eugenia decided to divorce Aleksander, and the matter was settled in favor of Jeremi. Wiśniowiecki also fought against the Tatars in 1640–46, whose raids on the south-east frontier of the Commonwealth