[10] How far these various and accumulated preferments imply a residence in England may be doubtful, but that Grey lived for some time in Oxford, possibly with the object of completing the acts required for the degree of Doctor of Divinity, is shown by the facts that he was elected Chancellor of the University, and held that office in 1440-1 and also during a part of 1442, and that later in this year he acted for a time as commissary.
Then, possibly after an interval spent in England, he went to Italy in order to apply himself more closely to the study of classical learning.
Grey's devotion to humanism and his patronage of learned men naturally found favour in the eyes of Pope Nicholas V. As early as 1450 the latter sought to obtain for him the bishopric of Lincoln, and failing to accomplish this, on 21 June 1454, on the elevation of Bishop Bourchier to the see of Canterbury, nominated him to the vacant bishopric of Ely.
Grey devoted much care to the collection of manuscripts, and wherever he resided constantly employed scribes to make copies of such books as he could not otherwise obtain.
It was his desire to make his collection the nucleus of a library for Balliol College, Oxford, to the building of which, as well as to that of the master's lodgings and of the old buttery and hall, he contributed largely.
The work was finished about 1477 by Robert Abdy, then master of the college, and enriched with some two hundred manuscripts, the bishop's gift.
Of these, many were destroyed in the reign of Edward VI and during the English Civil War, and by Wood's time few of the miniatures in the remaining volumes had escaped mutilation.
He devoted himself rather to the charge of his diocese, and still more probably to his learned interests, which were reputed to extend not only to Greek but also to Hebrew, while in his palace on Holborn he maintained the same stately establishment as that for which he had been famous on the continent.
On 26 August 1471 he was named first on a commission of fifteen to hold a diet at Alnwick to deal with the infractions of the truce with Scotland, and in the following March to treat with the Scots ambassadors at Newcastle-upon-Tyne on 25 April, and again on 16 May he was entrusted with a similar negotiation.
After Easter, he quit his London palace for Ely, and then, as his weakness increased, he removed to his neighbouring manor of Downham.