Members of the dynasty were traditionally Catholic, and the early Capetians had an alliance with the Church. The French were also the most active participants in the Crusades, culminating in a series of five Crusader kings – Louis VII, Philip Augustus, Louis VIII, Louis IX, and Philip III. The Capetian alliance with the papacy suffered a severe blow after the disaster of the Aragonese Crusade. Philip III's son and successor, Philip IV, humiliated Pope Boniface VIII and brought the papacy under French control. The later Valois, starting with Francis I, ignored religious differences and allied with the Ottoman sultan to counter the growing power of the Holy Roman Empire. Henry IV was a Protestant at the time of his accession, but realized the necessity of conversion after four years of religious warfare.