The Christianization of this Frisian and Saxon territory began in 780. By the year 1000, part of the organized church came under the archdiocese of Hamburg Bremen and part under the diocese of Osnabruck. In 1050 the duchy of Oldenburg was formed. The Reformation era found Oldenburg opening slowly to Lutheran, then to Calvinist, and – via the city of Munster – also to Anabaptist influences. The Lutheran forces won out. In 1573, the first Lutheran church order was introduced, and Calvinists and Anabaptists were denied freedom of worship.

During the Enlightenment period and under a change of political rule, still another church order was enacted, heavily influenced by rationalism. The 19th century brought renewal in the church and a restoration of confessional emphasis. A specifically Lutheran commitment reasserted itself during the church struggle of the 1930s and early 1940s when a scripturally founded confession of faith was of vital importance. This kind of emphasis underlay the subsequent church constitution of 1950 – still in effect – which is itself a confessionally based and ecumenically oriented document. When the United Evangelical Lutheran Church in Germany (VELKD) was organized in 1948, Oldenburg did not join. The church is headed by a bishop. The synod is the church’s legislative body.