In 1253 he was invested by the Pope in the Kingdom of Sicily and Apulia. At about this time he was also made Earl of Chester. These were of little value as the real King of Sicily was still living and the Earldom of Chester was transferred to his elder brother Edward. Edmund soon obtained, however, important possessions and dignities, for soon after the forfeiture of Simon de Montfort in 1265, Edmund received the Earldom of Leicester and Lancaster and also the honour of the Stewardship of England and the lands of Nicolas de Segrave.
He was married twice. First to Aveline de Forz, Countess of Albemarle, in 1269, and then in Paris, France on February 3, 1276, to Blanche of Artois. That same year he became the Count of Champagne and Brie in France. With Blanche he had four children: