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 also played a significant role in the schism.

Although rarely included in modern-day ecumenical dialogues, for centuries these "other issues"--the beardlessness of the Latin clergy, the Western use of unleavened bread in the Eucharist, and the doctrine of Purgatory--were among the most frequently cited reasons for the dispute between East and West. Disagreements about bread, beards, and the state of souls after death may not, at first, appear to be church-dividing issues, but they are the nevertheless among the reasons why the church today is divided. This was a schism over azymes long before it was a schism over the primacy of the Bishop of Rome, and the beardlessness of the Latin clergy was cited as a reason for breaking communion with the Latin Church prior to all the subsequent arguments about the wording of the Nicene Creed. To understand the schism between East and West, Siecienski contends, we must grasp not only the reasons it remains, but also the reasons it began.