Katholisches Bistum der Alt-Katholiken in Deutschland

Immediately after the First Vatican Council in 1870, some German theologians organized a meeting of theologians from various universities and lay people to protest against the new dogma of the infallibility and universal jurisdiction of the bishop of Rome (Königswinter Declaration 14.8.1870). A second meeting drew up a formal manifesto in which it declared that the "First Vatican Council" defining the infallibility was not a true council, for it was neither free, nor unanimous, nor ecumenical. After the opponents were all excommunicated by the Vatican, a bishopric was established in Germany, which chose a bishop who was consecrated in 1873 by the Dutch Old-Catholic bishop of Deventer (Netherlands). Reforms long needed were made and carried out with success, such as a synodal structure of the church, the liturgical use of German, and permission for clerical marriage. The diocese of the Old-Catholics was recognized as a "Catholic Diocese" by the king of Prussia and the grand dukes of Hessen and Baden.

The Old-Catholics are among the pioneers of the ecumenical movement. A first Old-Catholic Congress was held in Munich in 1871, attended by members of Anglican, Orthodox and Lutheran churches. In 1874-75 two conferences were held in Bonn invited by the standing committee of the synod, to promote Christian unity. In 1889 the Old-Catholic bishops in Europe agreed to form the Union of Utrecht. Since 1931 full communion is practised with the Anglican churches ("Bonn Agreement"), and more recently with the Philippine Independent Church, the Spanish Reformed Episcopal Church and the Lusitanian Church of Portugal. Dialogue with the Orthodox churches continues. An agreement on eucharistic hospitality was signed with the Evangelical Church in Germany (EKD) in 1985. The Catholic diocese of the Old-Catholics continues to work for unity among Christians by witnessing to the truth of the gospel and by emphasizing the permanent need for reforms in the church.

Priests are trained at the Old-Catholic seminary of the university of Bonn and the diocesan seminary "Johanneum". Since 1994 all the ordained ministries are open to women. The first woman priest was consecrated in 1996. The church is involved in diaconal work and counselling for families, and has a "Life and Faith" centre. In 1993 an Ecumenical Franciscan Fraternity was founded near Berlin, which offers shelter and spiritual care for homeless and unemployed men. Since 2004 the small monastic order of Port Royal, an ecumenical Cistercian community which was founded in 1999, is under the jurisdiction of the Catholic diocese.