John Mowbray, 3rd Duke of Norfolk further been suggested that his comic catchphrase was deliberately intended to invoke Sir John Falstaff, one of Shakespeare's best known characters, for the audience. In Shakespeare's "Henry IV, Part 2", Justice Shallow refers to Falstaff as having once been a page to "Thomas Mowbray, Duke of Norfolk", Mowbray's grandfather. Falstaff is commonly considered to be a fictional representation of either Sir John Oldcastle or Sir John Fastolf—or possibly an amalgamation of the two—both of whom are variously associated with Mowbray. John Mowbray, 3rd Duke of Norfolk John Mowbray, 3rd Duke of Norfolk, KG, Earl Marshal (12 September 1415 – 6
John Oldcastle in the parliament of 1404, later serving as a justice of the peace, and was High Sheriff of Herefordshire in 1406–07. In 1408 he married Joan, the heiress of Cobham — his third marriage, and her fourth. This resulted in a significant improvement of his fortune and status, as the Cobhams were "one of the most notable families of Kent". The marriage brought Oldcastle a number of manors in Kent, Norfolk, Northamptonshire and Wiltshire, as well as Cooling Castle, and from 1409 until his accusation in 1413 he was summoned to parliament as Lord Cobham. At some point in his