History, The Jagiellonian Dynasty

The second dynasty of Polish kings, the Jagiellonians, was founded by Jagiello, grand duke of Lithuania. In 1386 Jagiello married Jadwiga, queen of Poland, a grand niece of Kazimierz III, and ascended the throne as Wladyslaw II Jagiello. Roman Catholicism was introduced into Lithuania, a predominantly pagan country, by Wladyslaw, who was converted on his accession. In 1410 Polish and Lithuanian armies under Wladyslaw won a decisive victory at Grunwald over the Teutonic Knights, thereby raising Poland to a leading position among European nations. Thereafter, until 1569, a single sovereign usually ruled both states.

Under the Jagiellonian dynasty, which lasted until 1572, Poland attained great heights of power, prosperity, and cultural magnificence. Kazimierz IV, who ruled from 1447 to 1492, conducted a protracted and successful war (1454-1466) against the Teutonic Knights. In 1466, by terms of the Peace of Torun, which terminated the conflict, he secured West Prussia, Pomerania, and other territories. The landed gentry and lesser nobility acquired extensive privileges during Kazimierz’s reign, mainly at the expense of the peasantry. The Sejm, a parliamentary body that evolved out of earlier assemblies of nobles and other social groups, began to assume greater importance. The succeeding Jagiellonian kings, notably Zygmunt I, were generally victorious in the military and diplomatic struggles of the period, despite some setbacks in the east. In 1569 Zygmunt II Augustus united the two realms of Poland and Lithuania. The country was officially termed the Commonwealth (Rzeczpospolita). Protestantism, which made many converts among the nobility in the middle years of the 16th century, ceased to be significant after 1600.

With the death of Zygmunt II Augustus, last of the Jagiellonians, in 1572, the Polish nobility and gentry (Szlachta) successfully concluded a prolonged campaign for complete control of the country. A regime of elected kings was instituted with the power of election vested in the Sejm, then a bicameral body consisting of the lesser and greater nobility. One important aspect of this system was to be the liberum veto, which made it possible for any member of the Sejm to prevent the passage of legislation. The constitution also sanctioned the formation of military confederations of nobles.