The spiritual head of Orthodox Christians worldwide formally handed over a decree granting independence to the Ukrainian church to the head of Ukrainian spiritual leader, marking an historic split from Russia which Ukrainian leaders see as vital to the country’s security.

The decree, granting “autocephaly”, was signed by Ecumenical Patriarch Bartholomew at a service with the head of the Ukrainian church Metropolitan Epifaniy and President Petro Poroshenko in St George’s Cathedral in Istanbul.

“I want to thank the millions of Ukrainians around the world who responded to my appeal to pray for the church to be established,” Poroshenko said at a ceremony accompanied by solemn liturgical singing.