Sir John Oldcastle of Martyrs". Oldcastle was also a minor character in the early Elizabethan history play the "Famous Victories of Henry V" (c. 1586?), which is generally thought to have been one of Shakespeare's sources for his plays on Henry IV and Henry V. The genesis of "Sir John Oldcastle" is crucially linked to the fact that when Shakespeare's "Henry IV" plays premiered on stage in 1597–98, the character Sir John Falstaff was called Sir John Oldcastle. This is indicated by abundant external and internal evidence. The change of names, from "Oldcastle" to "Falstaff," is mentioned in seventeenth-century works by Richard James
Sir John Oldcastle it is generally thought, because of political pressure: the historical Oldcastle was not only a Protestant martyr, but a nobleman with powerful living descendants in Elizabethan England. These were the Lords Cobham: William Brooke, 10th Baron Cobham (died 6 March 1597), was Warden of the Cinque Ports (1558–97), Knight of the Order of the Garter (1584), and member of the Privy Council (1586–97); his son Henry Brooke, 11th Baron Cobham, was granted the paternal post of Warden of the Cinque Ports upon his father's death, and made a Knight of the Order of the Garter in 1599. Even more so,