He visited France again on diplomatic business on 30 November 1477, and on 11 August 1478, to conclude the espousals of Edward's daughter Elizabeth and Charles, son of the French king.
Two years later he was sent to demand the fulfilment of this marriage treaty, but the prince, now Charles VIII, king of France, refused to carry it out, and the match was broken off.
In 1478 he was made treasurer of Exeter,[2] prebendary of St. Decuman's, Wells Cathedral,[3] and about the same time master of St. Julian's Hospital, Southampton, a post which he still retained twenty years later.
Probably by the favour of King Edward V, who granted him the temporalities of the see on 21 May, Langton was advanced in 1483 to the bishopric of St. Davids;[5][6] the papal bull confirming the election is dated 4 July,[5] and he was consecrated in August or September.
[1] Before his death he had given 10 pounds towards the erection of Great St. Mary's Church, Cambridge, and in 1497 a drinking-cup, weighing 67 ounces, called the 'Anathema Cup,' to Pembroke Hall.