The jealousy and anger of many nobles were aroused by Mortimer's use of power, which in many ways was tenuous. In 1328 Simon de Mepham, reportedly a Lancastrian at court, was elected Archbishop of Canterbury without controversy. However, the feuding would not stop. The day Parliament opened on 15 October Thomas of Lancaster's nemesis, Sir Robert Holland was murdered by highway robbers. Whereupon March swore on Mepham's cross that he knew nothing of it. Nonetheless the King decreed an indictment; he would be judged at law against the standards of Magna Carta. With Parliament adjourned on 31 October, he was able to slip away to his estates on the Marches. The two earls’ lethal enmity, and enforced absence from the King's presence, rendered their motives almost equally suspect to rowdy Londoners. The young king would have to raise an army of archers if he was to defend his throne from a northern rebellion controlled from Lancaster. In charge of the army Lancaster blamed Mortimer and his queen for the debacle, and the highly contentious Treaty of Edinburgh–Northampton with the Scots.