Henry VII. Charles VIII agreed to withdraw all backing from Warbeck after an English expedition had laid siege to Boulogne. He was publicly recognized as Richard of Shrewsbury by Margaret of Burgundy, widow of Charles the Bold, sister of Edward IV, and thus the aunt of the Princes in the Tower. Whether Margaret—who left England to marry before either of her nephews were born—truly believed that the pretender was her nephew Richard, or whether she considered him a fraud but supported him anyway, is unknown, but she tutored him in the ways of the Yorkist court. Henry complained to Philip of Habsburg, Duke of Burgundy, about the harbouring of the pretender. When Henry was ignored, he imposed a trade embargo on Burgundy, cutting off important Burgundian trade connections with England. The pretender was also welcomed by various other monarchs and was known in international diplomacy as the Duke of York. At the invitation of Duke Philip's father, Emperor Maximilian I, in 1493, he attended the funeral of the Holy Roman Emperor Frederick III and was recognised as King Richard IV of England. Support in England (Perkin Warbeck conspiracy) Pro-Yorkist sympathy in England involved important figures making it known that they were prepared to back Warbeck's claims. These included Lord Fitzwater, Sir Simon Montfort, Sir Thomas Thwaites (ex-Chancellor of the Exchequer), Sir William Stanley (the Lord Chamberlain) and Sir Robert Clifford. Clifford went over to mainland Europe and wrote back to his friends to confirm Warbeck's real identity as Prince Richard. King Henry ordered the group of supporters to be rounded up and put on trial. All were duly arrested, together with William D'Aubeney, Thomas Cressener, Thomas Astwode, Robert Ratcliff and others. Lord Fitzwater was sent as a prisoner to Calais and later beheaded for trying to bribe his gaolers. In show trials in January 1495, all the conspirators were initially condemned to death, although six, including Thwaites, were then pardoned and their sentences commuted to imprisonment and fines. Within days Sir Simon Montfort, Robert Ratcliff and William D'Aubeney were beheaded at Tower Hill and Cressener and Astwode pardoned at the block. Later the same month Sir William Stanley was also beheaded. Other members of the group were imprisoned and fined. Sir Robert Clifford was pardoned and rewarded for revealing the names of the conspirators. First landing in England and support in Scotland (1495–1496) On 3 July 1495, funded by Margaret