The government declared the Church of Greece to be autocephalous in 1833 in a political decision of the Bavarian regents acting for King Otto, who was a minor. The decision roiled Greek politics for decades as royal authorities took increasing control.
Signing of the tomos
In the end, the Ecumenical Patriarchate of Constantinople decided on a compromise: the Ecumenical Patriarchate agreed to give autocephaly to the Church of Greece through a tomos which was dated 29 June 1850.