Prussia (province)

During the Reformation endemic religious upheavals and wars occurred, and in 1525, the last Grand Master of the Teutonic Knights, Albert of Brandenburg, a member of a cadet branch of the house of Hohenzollern, resigned his position, adopted the Lutheran faith and assumed the title of "Duke of Prussia." In a deal partially brokered by Martin Luther, Ducal Prussia became the first Protestant state. In 1618 the dukedom of Prussia passed to the senior Hohenzollern branch, the ruling Margraves of Brandenburg.

The ducal capital of Königsberg (now the Russian city of Kaliningrad) became a centre of learning and printing, one of its noted sons, the leading mathematician and astronomer Johann Müller Regiomontanus (1436-76), naming himself after the Latin form of the city's name. In 1492 a life of Saint Dorothy of Montau, published in Marienburg/Prussia, became the first printed publication in Prussia.

The second Treaty of Thorn had left eastern Prussia as a fief of the Polish crown. In 1660, after the Second Northern War between Sweden, Poland and Brandenburg, the Treaty of Welawa (Wehlau) granted full sovereignty to Frederick William I, the "Great Elector" of Brandenburg, as Duke of Prussia. The treaty also prescribed that when the Hohenzollern ruling house dies out, the land would revert to the Polish crown. (Hohenzollern rule expired in 1918, when Wilhelm II of Germany abdicated as German Emperor and King of Prussia. With the Treaty of Brest Litowsk Germany/Austria re-installed the Polish crown, but it was overthrown with the Treaty of Versailles.