He was one of the many deponents who gave evidence in Scrope v Grosvenor (decided in 1389), one of the earliest heraldic law cases brought in England, at which time he stated his age as 105.
According to Nicolas (1832), he descended from a younger branch of the family of Sully, lords of the manor of Iddesleigh in Devonshire, and appears to have succeeded to that property as heir male.
[10] His Garter stall plate does not survive but was recorded by the antiquarian Ashmole (d.1692)[11] as showing arms of Ermine, four barrulets gules with crest Two bull's horns.
[12] His family's arms are however given differently by the Devon historian Sir William Pole (d.1635) as Ermine, three chevrons gules[13] It appears that he passed the greater part of his life in the field, and that he was the "hero of a hundred battles."
Sully was in Gascony with the Black Prince in 1355 and 1356, and a payment was made to him at Bordeaux on 1 October 1355 by the hands of Richard Baker his esquire.'
He seems to have then retired from public life, attended by Richard Baker his faithful esquire, who, having partaken of his master's toils and dangers, became the companion of his latter years.
The following anecdote of a Sir John Sully is related by Pole:[14] His action was deemed by the Duchess of Cleveland (1889) "a childish excursion into Tom Tidler's Ground."
[21] The other, next to the effigy of his wife, is in Crediton Parish Church on a chest tomb ,[22] in the east chapel of the south aisle.