‘Tis impossible to be sure of any thing but Death and Taxes.
Christopher Bullock (1690?-1724) English actor and dramatist
The Cobler of Preston [Toby Guzzle] (1716)
(Source)
Earliest spotting of the phrase; if not popular before, it was subsequently picked up by a number of sources prior to the more famous formulation by Benjamin Franklin in 1789. More discussion: Nothing Is Certain, Except Death and Taxes – Quote Investigator.
