In the later folios (third onward) the character is called "Fastolf", to differentiate him from a separate character in HENRY IV, PART 1 and 2 (and eventually THE MERRY WIVES OF WINDSOR) who had originally been called Sir John Oldcastle until he Oldcastle Family objected to the nomenclature and the name of Prince Hal's dissolute friend was changed to Falstaff, thus instigating the character in HENRY VI (written long before HENRY IV) having his name changed from "Falstaff" to "Fastolf".
If Tom Hanks is going to play "Fastolf" in HENRY VI, Parts 1, 2 & 3, it'd be a bit lopsided casting-wise. |