Richard of Cornwall was born in 1209 as the youngest son of King John. His life of adventure made him one of the wealthiest and most widely travelled men of his era. Praised for his diplomatic and organisational skills, he led the last successful crusade to the Holy Land and was elected king of Germany. At home he was indispensable to his brother Henry III, but he resented his dependence on him and often equivocated his support. When his brother-in-law...