FEDERICO GUGLIELMO III, king of PRUSSIA. — Born on 3 August 1770 in Potsdam, died on 7 June 1840 in Berlin. Having ascended the throne in 1797, in 1801, by the Treaty of Lunéville, he ceded the lands on the left bank of the Rhine to France; but two years later, with the secularization of the German ecclesiastical states, he received in compensation the bishoprics of Hildesheim, Paderborn, Münster, and other territories. Forced into the disastrous Peace of Tilsit in 1807 and into an alliance with France in 1812, F. G. took advantage of Napoleon’s defeat in Russia to free himself from the French yoke. Having declared war on France, F. G., together with the emperors of Austria and Russia, entered Paris in triumph.
After the Congress of Vienna, he remained consistently faithful to the policy of the Holy Alliance.
Attached to Lutheranism, he became concerned about the considerable number of conversions to the Catholic faith among Prussian citizens who were coming to Rome at that time. He therefore wished to establish a German evangelical community in the Eternal City. In 1839 he sought to promote the union of the Calvinists with the Lutherans of his kingdom by establishing the Evangelical Church of Prussia (Evangelische Kirche der Altpreussischen Union). Toward Catholicism, the King was tenaciously hostile, obstructing the bishops in various ways
in the exercise of their ministry, and tending to reduce the Church to a handmaid of the State.