In 1817, King Frederick William III of Prussia ordered the Lutheran and Reformed churches in his territory to unite, forming the Evangelical Church of the Prussian Union, a predecessor to today's Union of Evangelical Churches. As the uniting of Lutheran and Reformed Christians in Germany proceeded, some Lutheran groups dissented and formed independent churches, especially in Prussia, Saxony, Hanover and Hesse. These Lutherans held that Reformed doctrine and Lutheran doctrine are contradictory on many points (especially on the nature of the Real Presence of Christ in the Lord's Supper), and that such doctrinal differences precluded altar fellowship. So in the 1820s and 1830s Lutherans in Prussia and their congregations formed a new Lutheran church, recognised by the king in 1845 as the "Evangelisch-Lutherische Kirche in Preußen" (Evangelical Lutheran Church in Prussia). It was seated in Breslau and presided over by the "Oberkirchenkollegium" (Supreme Church Collegial Body).