In 1322 he supported his halfbrother, Edward II, King of England,
          against the coalition of the marcher lords and Thomas, 2nd Earl of
          Lancaster, who were seeking to force the expulsion of Edward's hated
          favourites, the Despencers. Edmund besieged Thomas of Lancaster's
          Yorkshire stronghold of Pontefract and witnessed his execution in
          1322.
               In 1324 Edward made him lieutenant of Aquitaine, where he faced
          an invasion by Charles de Valois. About Christmas 1325 he married
          Margaret Wake and they became the parents of three children. In 1326
          Edmund joined Isabella, Edward II's queen, in her conspiracy against
          her husband, and was one of the council appointed to govern for the
          young Edward III in 1327 after the king's forced abdication.
               He resisted Isabella's ascendancy and that same year she
          implicated him in a plot to free Edward II and had him beheaded in
          1330.
 

Source: Leo van de Pas