He was twice elected Archbishop of Canterbury, but his personal life—which included a long-term mistress who was rumoured to have borne him four sons—prevented his confirmation by the papacy.
He continued to enjoy the king's trust until his death in 1292; one historian has suggested that Burnell may have been the most important royal official of the 13th century.
[7] After Simon de Montfort's victory at the Battle of Lewes in 1264, Burnell continued to serve Edward, and was named the prince's clerk in December 1264.
Eventually Pope Gregory X set Chillenden aside and installed his own choice in the see, Robert Kilwardby.
During the regency Burnell supervised a parliament, dealt with raids on the Welsh Marches and resolved a trade conflict with Flanders.
[15] King Edward sent a deputation,[16] including the eventual appointee, John Peckham, to secure Nicholas' confirmation of the election.
[2] Edward made one final attempt to promote his friend to a wealthier see in early 1280, when Burnell was nominated to become Bishop of Winchester,[18] but Pope Nicholas III quashed the election[19] on 28 June 1280.
He heard many requests and petitions from those who desired patronage or other advancements, and was diligent and active in dealing with routine business.
[23] Keeping the peace in the realm and the extension of royal jurisdiction to cover rape was dealt with in the statutes from 1285, along with a number of other issues.
They were first issued in 1278, after earlier attempts to recover royal rights through parliament unintentionally resulted in too much work for that body.
[26] The Wardrobe had developed as a less formal department for the collection and distribution of money, but under Edward had effectively become a treasury for warfare.
A Chancery memorandum of 1280 records that the chancellor, along with the other ministers, now had the duty of sorting the many petitions that came into the government and only passing on the most urgent to the king.
[2] Burnell was active in the king's foreign policy, especially towards France, Scotland and Wales, and undertook a number of diplomatic missions to those countries.
The historian Michael Prestwich therefore argues that the first half of Edward's reign was the period when Gascony enjoyed its most successful government under the Plantagenets.
Burnell was present during Edward's conquest of Wales in the 1280s; he witnessed documents in Rhuddlan in 1282, and subsequently at Conwy and Caernarfon.
[2] He amassed great wealth, and acquired numerous estates in Shropshire, Worcestershire, Somerset, Kent, Surrey and elsewhere.
At Acton Burnell the bishop's quarters were well away from the building's main public spaces, and included a latrine.
[45] Burnell was a dominant figure during the first part of Edward's reign, and he controlled most aspects of royal administration.
[14] He was involved not only in domestic issues but also in foreign relations,[46] a responsibility he retained for two decades after Edward's return to England in 1274.