In the 1820s, two English brothers, John Carter Allen (1795–1872) and Charles Manning Allen (1802–1880) adopted the names John Sobieski Stuart and Charles Edward Stuart, moved to Scotland, became Roman Catholics, and about 1839 began to claim that their father, Thomas Allen (1767–1852), a former Lieutenant in the Royal Navy, had been born in Italy the only legitimate child of Prince Charles Edward Stuart and his wife Princess Louise of Stolberg-Gedern. They claimed that Thomas had, for fear of kidnapping or assassination, been brought secretly to England on a ship captained by their grandfather, Admiral John Carter Allen (1725–1800), and adopted by him. Thomas was thus, they claimed, 'de jure monarch of England in place of the then reigning sovereign Queen Victoria'.
"They succeeded in fabricating around them an aura of bogus royalty which attracted the allegiance of a few romantic Jacobites in Victorian times". Herbert Vaughan called their story "an impudent fabrication" and "an unblushing fraud" but it was as Sir Charles Petrie wrote "proof of the hold which the House of Stuart has never ceased to exercise upon popular imagination in the British Isles, so that ... if a man were to declare himself the heir to the Yorkist or Tudor dynasty, he would attract but little attention, yet if he claim to be a Stuart he will find hundreds ready to believe him".
The brothers' two publications, Vestiarium Scoticum (Edinburgh, 1842) and The Costume of the Clans (Edinburgh, 1845), described by the historian Hugh Trevor-Roper as "shot through with pure fantasy and bare faced forgery", have been sources widely used by the tartan industry in Scotland.
Family background
The brothers' grandfather, John Carter Allen (1725–1800), an admiral in the British navy, had three children: the above-named Lieutenant Thomas Allen (1767–1852), Jane or Jean Allen (c.1768–1829) who married Thomas Robinson, a widower, at Brighton in 1788, and Admiral John Allen (1771–1853). The three were named in John Carter Allen's will, though he bequeathed only £100 to Thomas and £100 and a pair of silver candlesticks to Jane, leaving £2,200 and the residue to John. This disparity caused comment and some have speculated that Thomas was illegitimate, but an income had been guaranteed to him under his marriage settlement in 1792.
However, additional research in 2014 showed that John Carter Allen did not marry until 1780 and that his three children were all illegitimate, born in a period in which he held no commission. The three were named 'natural children of John Cator Allen' in the twelfth of sixteen codicils to the will of Elizabeth Arnold, his first wife's mother, dated in 1788 and proved in 1789. She left them twenty guineas each and £1,000 to their father. The identity of their mother(s) has not been found. There was much tension in the family later and at one time the youngest son, John, was heard to say of Thomas, 'he is no brother of mine'.
John Carter Allen himself had been baptised at St Dunstan in the West in 1724/5, the son of Carter Allen (1700–1734), an attorney in the parish of St Clement Eastcheap in the City of London, who had married Emma Hay or Hays at St Giles, Camberwell, in 1724. These details also were not known until 2014. Contemporaries of John Carter Allen had said at his death in 1800 that the late Lord Hillsborough (who died in 1793 and for whom John Carter Allen's younger brother William Allen (1729–1811) had worked as an office clerk) had said that 'he had a claim to the title of Erroll ... as being descended from the old Earl Hay in the male line', a worthless statement as the peerage had become extinct in the male line in 1717, but believed by Thomas who added Hay to his name.
However, the uncertainty of their descent and the romantic nature of the various claims surrounding them greatly influenced the two brothers. They also added Hay to their names and in 1822 the eldest son, as John Hay Allan, published a Genealogical table of the Hays, from William de Haya, cupbearer to Malcolm IV, 1170, down to 1840, with all the branches (Edinburgh, 1840), though his descent is not shown in the book and the parentage of Emma Hay or Hays has not been found.