His "historical review of the stage", Roscius Anglicanus (1708), is an invaluable source for historians both of Restoration and of Stuart theater.
Downes first enters the theatrical record in 1664, when he was registered by the Lord Chamberlain as a member of William Davenant's troupe under the patronage of the Duke of York.
He retired around 1706, and may be the John Downes recorded as buried in St Paul's, Covent Garden, in June 1712.
He provides cast lists for countless plays, information on the success or failure of many pieces, and incidental comments on his own preferences.
Still, as Sidney Lee notes, his work along with two or three other memoirs, "is practically all to which we have to trust for our knowledge of the Restoration stage."