In 1517 a German friar, Martin Luther, had first given voice to the universal discontent, by opposing the immoral practice of selling "indulgences," or papal letters remitting penances for sins, in return for money. He had followed this up by preaching against many other papal abuses, and, when Leo X. replied by excommunicating him, he began to attack the whole system of the mediaeval Church--inveighing against the Pope's spiritual supremacy, the invocation of saints, the celibacy of the clergy, the adoption of the monastic life, and many other matters. He was supported by his prince, Frederick, Elector of Saxony, and a great part of Germany at once declared in his favour (1517-21). [Sidenote: =The Church in England.=] England was not at first very much affected by the revolt of Germany against the papacy. The English Church was far less corrupt than those of France or Italy, and though full of abuses, was not really unpopular with the nation. It still retained much of the old national spirit, and was not the mere slave of the Pope. Neither king nor people showed any signs of following the lead of the Germans. Henry wrote a book to prove Luther's views heretical, and received in return from Leo X. the title of Defender of the Faith, which English sovereigns still display on their coinage. Wolsey devoted himself to practical reforms, leaving doctrine alone. His first measure was to suppress many small and decayed monasteries, and to build with their plunder his great foundation of Cardinal's College, afterwards known as Christ Church, in the University of Oxford. [Sidenote: =Henry and Queen Catherine.=] It was not till about 1527 that England began to be drawn into the struggle which was convulsing all continental Europe, and then the cause of quarrel came from the king's private affairs, and not from any doctrinal dispute. It will be remembered that Henry had been affianced by his father to Catherine of Aragon, the widow of his brother, Arthur Prince of Wales. Marriage with a deceased brother's wife being illegal, a papal dispensation had been procured to remove the bar, and Henry had married Catherine on his accession, so that he could not plead compulsion on the part of his father. The marriage was not a wise one, for the queen, though a very gentle and virtuous woman, was six years older than her husband, had no personal attractions, and was delicate in health. All the children whom she bore to Henry died in infancy--except one, the Princess Mary. By 1527 Catherine was a confirmed invalid, and showed all the signs of premature old age, though she was only forty-two. [Sidenote: =Henry desires a divorce.=]