It is important to learn about multiple religious traditions because religion has historically been a driving force behind many important historical events. Understanding multiple traditions also helps to foster an understanding of other cultures, which are often heavily influenced by religion. In the Middle Ages, the power of the Pope rivaled that of kings, and monarchs considered the imprimatur of the Pope to be a necessity, with many willing to make concessions to Rome to secure the Pope's blessing. The Anglican movement in England was sparked by a dispute between King Henry VIII and the Vatican over whether Henry, as king, was head of the Roman Catholic Church in England. In another instance, a dispute between the Pope in Rome and the Patriarch in Constantinople led the two to excommunicate each other, creating the first major schism in the Christian world.