Claim: Through the marriage of William II of Sicily with Joan of England, he became the brother-in-law of Richard I of England, who would prove to be just as adventurous as his kinsman.
Evidence: In 1174 and 1175 William made treaties with Genoa and Venice and his marriage in February 1177 with Joan, daughter of King Henry II of England and Duchess Eleanor of Aquitaine, marks his high position in European politics. Richard was an important Christian commander during the Third Crusade, leading the campaign after the departure of Philip II of France and achieving considerable victories against his Muslim counterpart, Saladin, although he finalized a peace treaty and ended the campaign without retaking Jerusalem. From an early age, Richard showed significant political and military ability, becoming noted for his chivalry and courage as he fought to control the rebellious nobles of his own territory.