Henry III (1207–72) was the longest-serving monarch of England until the modern era. His reign began with a minority in perpetual crisis and ended after the constitutional issues of the day had been settled on the battlefield. Nevertheless, most of his 56 years on the throne were peaceful and prosperous, and saw extraordinary achievements, from the rise of the parliamentary state to the great cathedrals of the land—including Henry’s own enduring contribution, Westminster Abbey. Here, historian Darren Baker presents a detailed account of this fascinating and much maligned monarch who was able to survive at a time when others didn’t.