Having introduced the general reader to the Albigensian Crusade in The Perfect Heresy, journalist and historian Stephen O’Shea now expands his vision to encompass the history of the first thousand years of two of the world’s great monotheistic religions.

Using the framework of seven pivotal battles, from Yarmuk in 636 to Malta in 1565, O’Shea traces the convoluted history of Islamic/Christian interactions around the Mediterranean. It’s a dramatic story of conflict and betrayal, but with surprisingly uplifting localized interludes of hope and mutual respect. Unfortunately, the memory of those interludes – which include, say, coexistence and cultural flowering between the 8th and 11th centuries in Cordoba – has been largely suppressed by the fanatics on both sides, who see only winners and losers in the battle for souls.

Sea of Faith has, necessarily, a much broader focus than The Perfect Heresy, and that’s both a strength and a weakness here. The lives of the main historical figures flash in and out of Sea of Faith much more rapidly than those in the Albigensian Crusade. On the other hand, O’Shea’s talent for enlivening 1,000-year-old events, and his personal perspective on the modern landscape where all this history happened, help the larger story move along at a cracking pace.

The illustrations are relevant, and the casual reader’s memory is greatly aided by a timeline, a list of the multitude of characters, and a glossary. Even the 53 pages of endnotes, rich in digression and anecdote, are a pleasure to dip into. For the reader who wants to take things further, there is an extensive bibliography.

This is a fascinating and readable overview of a time in which the roots of the modern Middle East turmoil were firmly planted. It’s a story that reconfirms that no side has a monopoly on right or stupidity, and as such should be required reading for anyone who wants to understand our modern crusades.