TO A non-Christian, or even to a Christian who prefers to keep doctrine and worship as simple as possible, the Catholic and Orthodox churches can look pretty similar. Both use elaborate ceremonies of ancient origin and have multiple ranks of robed clergy; both claim continuity with the dawn of the Christian era; both have rich theological and scholarly traditions and generally, long institutional memories. Only an apparently tiny difference separates the versions they use of the creed setting out their basic beliefs in a triune God of Father, Son and Holy Spirit. Why, then, do the two religious bodies not simply unite? On February 12th Pope Francis and Patriarch Kirill of Moscow, the head of the Russian Orthodox church, will meet in Cuba. Though not unprecedented in the last ten centuries such a meeting is nonetheless unusual. Why?
