The Armenian Apostolic Church, whose origins go back to the mission of St. Thaddeus and St. Bartholomew, counts about seven million worshippers. As Christianity was already declared the state religion in Armenia in 301, the Armenian Church is considered to be the oldest Christian state religion. It belongs to the autocephalous Oriental Orthodox Churches, but has adapted to the Western Churches with regard to the ecclesiastical year and follows the Gregorian calendar. The head of the Armenian Apostolic Church, the Catholicos of Echmiadzin, bears the title "Supreme Patriarch and Catholicos of all Armenians". The Primate of the Diocese of the Armenian Church in Germany is Archbishop Karekin Bekdijian; he is based in Cologne. The number of parishes in Germany is 14, but they have only three churches of their own.

Further information can be found here:

http://armenische-kirche.de/