The reason Sir Roger may be referred to as 'the greatest traitor' is that treason was first legally defined in the wake of his misdeeds. A loyal knight and twice a governor of Ireland, he took arms against the king's favourite, Hugh Despenser, in 1321, and suffered imprisonment in the Tower of London after the king turned the royal army against him. Having escaped the Tower he fled to France, and there seduced the Queen of England (Isabella), returning with her at the head of an invading army in 1326. He captured the king, manipulated Parliament to depose him, then forced him to abdicate. He executed the Treasurer, while the Chancellor was murdered by his supporters. He subsequently faked the king's death in Berkeley Castle, and dominated the young king (Edward III), eventually forcing him to approve the execution of his own uncle, the Earl of Kent (third in line to the throne). He was eventually captured at Nottingham Castle and executed on a number of charges, many of which repeated that he had 'accroached royal power'. When asked to define this by Parliament in 1348, Edward III issued the Statute of Treason (1351), which was closely based on Mortimer's real and supposed crimes: killing the monarch, sleeping with the monarch's wife, making war against the King, and killing the Chancellor or the Treasurer. Further details on Mortimer and the faked death of Edward II in Berkeley Castle - which underpins much of his treasonable career - may be found in the recently published biography The Greatest Traitor: the life of Sir Roger Mortimer, 1st Earl of March, Ruler of England 1327-1330, by Ian Mortimer (no relation).