The head of the Church of Greece, Archbishop Ieronymos, will attend a service in Kiev on Sunday despite threats by the Russian Orthodox Church that it could split from the Ecumenical Patriarchate over possible recognition of the Ukrainian Church.

The service in Kiev, held to mark 1,020 years since the Christianization of the Russians, has taken on an air of controversy after Russian Patriarch Alexy II launched a verbal attack against the spiritual leader of Orthodox Christians, Ecumenical Patriarch Vartholomaios.

Vartholomaios responded yesterday by sending a letter to Alexy calling his remarks “insulting.”

Alexy had called for Orthodox leaders to boycott the service in Kiev but, in a vote held by Greece’s Holy Synod yesterday, it was decided by 11 votes in favor to one against that Ieronymos should go. He will be accompanied by the bishops of Chios and Preveza.