In John of Brienne: King of Jerusalem and Emperor of Constantinople, James Turner offers an in-depth exploration of one of the medieval world's most intriguing yet underappreciated figures. John of Brienne, who ascended from a relatively modest French aristocratic background, secured not one but two of the era's most prestigious crowns: King of Jerusalem and Emperor of Constantinople. Through a blend of personal ambition, strategic marriages, and opportune alliances, John navigated the turbulent political landscape of the Crusader States and the Byzantine Empire.

This book unveils the fascinating, often chaotic world in which John lived, charting his improbable rise to power and examining why his legacy fell short compared to his contemporaries like Richard the Lionheart or Philip II of France. Turner's account highlights both John's virtues as a tactician and diplomat, and his struggles as he swam against the tides of history. For anyone interested in the crossroads of Crusader politics, medieval kingship, and the shifting power dynamics of Europe and the Levant, this is a compelling read.