Old Lutherans were originally German Lutherans in the Kingdom of Prussia, notably in the Province of Silesia, who refused to join the Prussian Union of churches in the 1830s and 1840s. Prussia's king Frederick William III was determined to unify the Protestant churches, to homogenize their liturgy, organization and even their architecture. In a series of proclamations over several years the Church of the Prussian Union was formed, bringing together the majority group of Lutherans, the minority of Reformed. The main effect was that the government of Prussia had full control over church affairs, with the king recognized as the leading bishop.