The Catholic and Orthodox churches have been divided for nearly a thousand years. The issues that divide them are weighty matters of theology, from a dispute over the Nicene Creed to the question of the authority of the Pope. But while these issues are cited as the most important reasons for the split, they were not necessarily the issues that caused it. In Beards, Azymes, and Purgatory A. Edward Siecienski argues that other, seemingly minor issues...