Since knowledge is but sorrow's spy, It is not safe to know.

However it seems that this rumour stemmed from a comment attributed to Davenant by Samuel Butler: "It seemed to him [Davenant] that he writ with the very same spirit that Shakespeare [did] and seemed content enough to be called his son. He died in London on 7 April 1668 shortly after his final play The Man's the Master was first performed. He spent all of 1651 in the Tower of London where he continued writing Gondibert.

Along with Thomas Killigrew Davenant was one of the rare figures in English Renaissance theatre whose career spanned both the Caroline and Restoration eras and who was active both before and after the English Civil War and during the Interregnum.