Peter's Rock in Mohammed's Flood, from St. Gregory the Great to St. Leo III

"Peter's Rock in Mohammed's Flood" by Thomas W. Allies is a historical account written in the late 19th century. This work is part of a larger series titled "The Formation of Christendom" and provides an in-depth examination of the early Christian Church's evolution, particularly during the period from St. Gregory the Great to St. Leo III. The book's central theme revolves around the struggle for the unity and authority of the Christian faith amidst political turmoil and doctrinal disputes, especially in relation to the Byzantine Empire and the rise of Islam. The opening of the volume introduces the author’s intent, highlighting the significance of studying church history as a continuous narrative that reflects divine providence. Allies emphasizes the importance of the church's unity and how doctrinal disagreements threaten the integrity of the Christian Gospel. He sets the stage for examining the dynamic interplay between popes and emperors while addressing challenges from rival belief systems, including the emerging Islamic faith. The author aims to present a comprehensive view of how the early church navigated the complexities of governance, faith, and the evolving relationship with secular powers during a tumultuous and formative time in history.