On this date in 1499 Perkin Warbeck (born c. 1474), who claimed to be the rightful heir to the throne of England, was executed following an alleged attempt to escape from the Tower of London. He said he was Richard of Shrewsbury, the 1st Duke of York, who was presumed to have been murdered by his uncle, Richard III (1452 – 1485), in 1483. Warbeck had been imprisoned in the Tower by Henry VII (1457 – 1509) after a failed usurpation.

See 

http://www.history.com/this-day-in-history.do?action=tdihArticleCategory&id=5542&HPF_rid=36892318&HPF_mid=3070_T1_Url3

and

http://en.wikipedia.org/wiki/Perkin_Warbeck for more information.