These rival pretensions began to be heard as soon as it became evident that Henry VIII. would have no male heirs by Catherine of Aragon. In 1519, a year after the birth of the Queen's last child, Giustinian reported to the Venetian signiory on the various nobles who had hopes of the crown. The Duke of Norfolk had expectations in right of his wife, a daughter of Edward IV., and the Duke of Suffolk in right of his Duchess, the sister of Henry VIII. But the Duke of Buckingham was the most formidable: "It was thought that, were the King to die without male heirs, that Duke might easily obtain the crown".[517] (p. 182) His claims had been canvassed in 1503, when the issue of Henry VII. seemed likely to fail,[518] and now that the issue of Henry VIII. was in even worse plight, Buckingham's claims to the crown became again a matter of comment. His hopes of the crown cost him his head; he had always been discontented with Tudor rule, especially under Wolsey; he allowed himself to be encouraged with hopes of succeeding the King, and possibly spoke of asserting his claim in case of Henry's death. This was to touch Henry on his tenderest spot, and, in 1521, the Duke was tried by his peers, found guilty of high treason, and sent to the block.[519] In this, as in all the great trials of Henry's reign, and indeed in most state trials of all ages, considerations of justice were subordinated to the real or supposed dictates of political expediency. Buckingham was executed, not because he was a criminal, but because he was, or might become, dangerous; his crime was not treason, but descent from Edward III. Henry VIII., like Henry VII., showed his grasp of the truth that nothing makes a government so secure as the absence of all alternatives. [Footnote 517: _Ven. Cal._, ii., 1287. Buckingham's end was undoubtedly hastened by Wolsey's jealousy; before the end of 1518 the Cardinal had been instilling into Henry's ear suspicions of Buckingham (_L. and P._, iii., 1; _cf. ibid._, ii., 3973, 4057). Brewer regards the hostility of Wolsey to Buckingham as one of Polydore Vergil's "calumnies" (_ibid._, vol. iii., Introd., p. lxvi.).] [Footnote 518: _L. and P. of Richard III. and Henry VII._, i., 233.] [Footnote 519: See detailed accounts in _L. and P._, iii., 1284, 1356. Shakespeare's account in "Henry VIII." is remarkably accurate, except in matters of date.]