The claim was disputed by Windsor and Chertsey Abbey, and the question was argued before the privy council, which decided in favour of Westminster.
His capacity for business led Henry VIII to appoint him a member of the privy council, probably on his departure to France in 1513, as Islip's name first appears attached to a letter in September of that year.
[2] This peaceful discharge of ordinary duties was disturbed for Islip, as for most other Englishmen of high position, by the proceedings for the king's divorce.
In July 1529 Islip was joined with Burbank and others for the purpose of searching among the royal papers for documents to present to the legatine court of Wolsey and Campeggio.
But though Henry was bent upon his divorce, he could attend to minor matters; for in September 1531 he negotiated an exchange with the abbey of Westminster of sundry tenements reaching as far as Charing Cross, for which he gave them the site of the convent of Poghley, Berkshire, one of the lesser monasteries, dissolved by Wolsey, which had become forfeited to the crown.
Islip's fame as a custodian of the fabric of the abbey long remained, and his example was held as a model by Williams when he was dean of Westminster.