The Russian Orthodox Church has formally cut all ties with the Ecumenical Patriarchate in Istanbul:

In the biggest rift in modern Orthodox history, the Russian Orthodox Church has cut all ties with the Constantinople Patriarchate, effectively splitting from it after it granted independence to the Ukrainian Orthodox Church.

The Holy Synod, the governing body of the Russian Orthodox Church, has ruled that any further clerical relations with Constantinople are impossible, Metropolitan Hilarion, the head of the Russian Orthodox Church’s External Relations Department, told journalists, de facto announcing the breaking of relations between the two churches.

More:

The move comes days after the Synod of the Constantinople Patriarchate decided to eventually grant ‘autocephaly’ to the Ukrainian Orthodox Church, thus making the clerical organization, which earlier enjoyed broad autonomy within the Moscow Patriarchate, fully independent.

The move taken by Moscow arguably marks the greatest split in the history of the Orthodox Church since the Great Schism of 1054, which separated Catholics and Orthodox Christians, as it involves a break of communion between the biggest existing Orthodox Church – the Moscow Patriarchate – and the Constantinople Patriarch, who is widely regarded as a spiritual leader of the world’s Orthodox Christians, even though his status is nothing like that of the Pope in the Catholic Church.

Writing in the Catholic Herald a couple of weeks ago, Father Mark Drew gave a backgrounder on the historical and ecclesiological issues in play.

These are very deep waters. My natural sympathies lie with the Russians here, but I don’t know enough about the details to offer an informed opinion. I welcome your commentary in the comments thread — but please, be civil.