The choristers in his charge included his successor and eventual son-in-law Pelham Humfrey, as well as Henry Purcell, John Blow, William Turner, Robert Smith and Michael Wise.
[2] On reconstituting the choir of the Chapel Royal, Dussuaze states: A year after the opening of his Majesty's Chapel, the orderers of the music were "necessitated to supply superior parts of the music with cornets and men's feigned voices, there being not one lad for all that time capable of singing his part readily."
On 23 February 1660-1, Pepys mentions Cooke and his boy, apparently Pelham Humfrey, whom he heard make a trial of an anthem for the following day.
By November, 1663, the first set was properly trained, and Cooke had already obtained remarkable results.
On the 22nd Humfrey's first anthem, "Have Mercy upon Me, O God," was sung in his Majesty's Chapel, and Pepys remarks: "They say there are four or five of them that can do so much"; the other four being probably Smith, John Blow, Michael Wise and Tudway or Turner.Cooke was one of the five English composers who created music for Sir William Davenant's The Siege of Rhodes (1656), often called the first English opera.