in the princes' upbringing and well-being. Before he died, the king had promised to provide Edmund with substantial grants of land. In August 1306, Edward I signed a charter promising Edmund land worth 7000 marks a year, and in May 1307, 1000 marks were added to this. He probably intended to give the earldom of Norfolk to Thomas, while Edmund would receive the earldom of Cornwall, which had been left vacant after Edward I's cousin Edmund died without children in 1300. When Edward II came to the throne, however, he went against his father's wishes by granting the earldom of Cornwall to his favourite Piers Gaveston. According to the chronicle Vita Edwardi Secundi, this act was a grave insult to the king's younger brothers. Edward II, nevertheless, took steps to provide his half-brother with an income; grants made in 1315 and 1319 secured Edmund 2000 marks a year. In May 1321, Edmund received the strategically important Gloucester Castle, and further grants followed his creation as Earl of Kent on 28 July 1321. Edward II's close relationship with Gaveston had been a source of conflict at court, and Gaveston's execution by a group of rebellious barons in 1312 had brought the country to the brink of civil war. As Edmund came of age, he became an important member of the circle around his brother. In 1318, the Treaty of Leake was drafted as an effort to reconcile the opposing parties, and Edmund – as his first public act – was among the witnesses to sign this treaty. Further official appointments followed. In the spring of 1320 he took part in an embassy to Pope John XXII in Avignon, where the mission was to absolve the king of his oath to uphold the Ordinances, a set of restrictions imposed on royal authority by the baronage. Later that year, he joined his brother the king in Amiens, where Edward was paying homage to the French king. In October 1320, Edmund attended his first parliament. Civil war As the political conflict escalated into full-scale rebellion in 1321–22, Edmund played an important role in its suppression. The opposition stemmed from resentment against the king's new favourites, Hugh Despenser the Younger and Hugh Despenser the Elder. When Bartholomew Badlesmere, steward of the royal household, defected to the opposition, Edward made his youngest brother Lord Warden of the Cinque Ports in place of Badlesmere on 16 June.