Henry VIII was one of the most significant monarchs of England. Most famous for having six wives during the course of his tumultuous reign, he also did much to build England as a powerful nation-state, and, perhaps most significantly, separated the kingdom from the Catholic Church. Unable to conceive a male heir, Henry petitioned the Pope to annul his marriage to his first wife, Catherine of Aragon. When the Pope denied the King's request, he took the revolutionary step of declaring himself head of the Church of England, separating the kingdom from the Catholic Church. This move ushered in a decades-long conflict between England and Spain, the dominant Catholic power on the continent. It also significantly strengthened the English monarchy, and Parliament, by stripping the Church of lands and authority in England. Henry would go on to marry five more times, executing his wives Anne Boleyn and Catherine Howard for adultery, and divorcing Anne of Cleves. Jane Seymour died before Henry, and Katherine Parr was his wife at his death. He had one son, Edward VI, who succeeded him, but died soon after. Edward was succeeded by first Lady Jane Grey and then Henry's daughters Mary and Elizabeth, who became one of the most important monarchs in English history.