Prussian Homage in the context of "East Prussia"

East Prussia (German: Ostpreußen [ˈɔstˌpʁɔɪ̯sn̩] ) was a province of the Kingdom of Prussia from 1772 to 1829 and again from 1878 (with the Kingdom itself being part of the German Empire from 1871); following World War I it formed part of the Weimar Republic's Free State of Prussia, until 1945. Its capital city was Königsberg (present-day Kaliningrad). East Prussia was the main part of the region of Prussia along the southeastern Baltic Coast.

The bulk of the ancestral lands of the Baltic Old Prussians were enclosed within the later province of East Prussia. During the 13th century, the native Prussians were conquered by the crusading Teutonic Knights. After the conquest they were gradually converted to Christianity. As a result of the medieval Ostsiedlung, Germans became the dominant ethnic group, while Poles and Lithuanians formed sizeable minorities. From the 13th century, the region of Prussia was part of the monastic state of the Teutonic Knights. After the Second Peace of Thorn in 1466 it became a part of the Kingdom of Poland, either directly (Warmia) or as a fief (remainder). In 1525, with the Prussian Homage, the territory became the Duchy of Prussia, a vassal duchy of Poland. It gained full sovereignty in 1657, when Poland renounced its feudal rights in the Treaty of Bromberg.

The monarchs of Prussia were members of the House of Hohenzollern who were the hereditary rulers of the former German state of Prussia from its founding in 1525 as the Duchy of Prussia. The Duchy had evolved out of the Teutonic Order, a Roman Catholic crusader state and theocracy located along the eastern coast of the Baltic Sea. The Teutonic Knights were under the leadership of a Grand Master, the last of whom, Albert, converted to Protestantism and secularized the lands, which then became the Duchy of Prussia.

The Duchy was initially a vassal of the Kingdom of Poland, as a result of the terms of the Prussian Homage whereby Albert was granted the Duchy as part of the terms of peace following the Prussian War. When the main line of Prussian Hohenzollerns died out in 1618, the Duchy passed to a different branch of the family, who also reigned as Electors of Brandenburg in the Holy Roman Empire. While still nominally two different territories, Prussia under the suzerainty of Poland and Brandenburg under the suzerainty of the Holy Roman Empire, the two states are known together historiographically as Brandenburg-Prussia.

The Polish–Teutonic War of 1519–1521 (German: Reiterkrieg, lit. 'Rider's War', Polish: Wojna pruska, lit. 'Prussian War') was fought between the Kingdom of Poland and the Teutonic Knights, ending with the Compromise of Thorn in April 1521. Four years later, under the Treaty of Kraków, part of the Catholic Monastic State of the Teutonic Order became secularized as the Duchy of Prussia. The reigning Grand Master Albert of Hohenzollern-Brandenburg-Ansbach became the first Duke of Prussia by paying the Prussian Homage as vassal to his uncle, Polish king and grand Duke of Lithuania, Sigismund I the Old (1467–1548, reigned 1506–1548).