What queen's marriage was a condition of the promises in the Poland-Lithuanian union that was threatened to be severed by the Lithuanian Civil War?
Lithuanian Civil War (1432–38) The Lithuanian Civil War of 1432–1438 was a conflict over the succession to the throne of the Grand Duchy of Lithuania, after Vytautas the Great died in 1430 without leaving an heir. The war was fought on the one side by Švitrigaila, allied with the Teutonic Knights, and on the other by Sigismund Kęstutaitis, backed by the Kingdom of Poland. The war threatened to sever the Union of Krewo, the personal union between Poland and Lithuania. Švitrigaila's alliance with the Grand Master of the Teutonic Order, Paul von Rusdorf, launched the Polish–Teutonic War (1431–1435) but failed to secure victory for Švitrigaila.
Catherine Opalińska Catherine Opalińska (Polish: "Katarzyna Opalińska" ; 13 October 1680 – 19 March 1747) was Queen consort of the Polish-Lithuanian Commonwealth twice and Duchess consort of Lorraine through her marriage with Stanisław I of Poland.