John of Ibelin, count of Jaffa and Ascalon (d. 1266), was one of the foremost politicians in the kingdom of Jerusalem in the mid-thirteenth century; his family was prominent in the Latin East, and linked by ties of marriage to the royal dynasties of both Jerusalem and Cyprus. John's career and his ancestors' rise to prominence are the subject of the first half of this book. The second concentrates on John's most lasting achievement, his treatise on...