Some of you may be asking what a Jacobite Pretender is doing as the villain in a Napoleonic novel. (Or if you aren't, you should be.) As with everything else, you can blame that on Lord Vaughn. Of all my characters, Lord Vaughn is the most rooted in the eighteenth century. His manners, his mores, his mind-set — all look back to the heyday of the Whig aristocracy, to an era of refined wit rather than Romantic excess. Both the barge on the Thames and the pleasure gardens of Vauxhall, while still in use in the early nineteenth century, bear the savor of the prior century, just like Vaughn.
Like Vaughn, Jacobitism also properly belongs more to the eighteenth century than the nineteenth — which made it just the right sort of foil for Vaughn. The Jacobite cause, which gave successive Hanoverian Georges nasty nightmares, had its origin in the expulsion of James II from the throne in the Glorious Revolution of 1688. Glorious for some, but not for James's descendants, who spent the next century in ineffectual attempts to regain the throne. James II's son, known variously as James III, the Chevalier of St. George, or the Old Pretender, made a bid for the throne in 1715. After that failed, his son, Prince Charles Edward, popularly known as Bonnie Prince Charlie, made another attempt in 1745, which was brutally squashed on the battlefields of Scotland. Although the cause largely petered out with the death of Bonnie Prince Charlie in 1788, halfhearted plots continued to be made and toasts drunk well into the nineteenth century. George III cannily neutralized Charles's brother, the would-be Henry IX, by putting him on the royal payroll in 1801, thus forestalling any rebellions out of him, but Bonnie Prince Charlie's illegitimate grandson was still touting his right to the English throne as late as 1850.
Like Eloise, I spent a semester in grad school reading up on Jacobite activities and iconography. The motto spes tamen est una was indeed the slogan on a medal struck by Bonnie Prince Charlie for his child and heir — only that child was his illegitimate daughter, Charlotte, whom he created with the Duchess of Albany, rather than his apocryphal illegitimate son, James. Might Charles have had an illegitimate son of the right age? As Eloise pointed out, it's not an impossibility. His long-term mistress, Clementina Walkinshaw, left him in 1760 (driven away by his drunkenness, or so the story goes), leaving a convenient twelve-year gap until his marriage in 1772 to a German princess of irreproachable lineage, Louisa of Stolberg-Gedern (who also eventually left him). A child born during those twelve years would be just the right age to be the Black Tulip….
For those interested in learning more about Jacobitism in all its aspects, including its survivals into the nineteenth century, I highly recommend Paul Monod's excellent monograph on the topic, Jacobitism and the English People.
A few other legitimate historical characters and organizations were pressed into service for the purposes of this story. Thomas Paine was, in fact, a master corset-maker before becoming a writer of incendiary pamphlets. His pamphlet on the expected invasion of England by Bonaparte (imaginatively titled "To the People of England on the Invasion of England") wasn't actually published until 1804, but I took the liberty of moving it up a few months for dramatic effect. Joseph Priestley and his allegiances and experiments were also taken from his life. Priestley was, indeed, hounded out of England after his infamous "gunpowder" comment, and he did isolate "dephlogisticated air" or, as we now call it, oxygen. The Common Sense Society, named after Paine's famous pamphlet, was loosely based on the Revolution Society (lambasted by Edmund Burke in his Reflections on the Revolution in France), of which Priestley was a member. Priestley's disciple, Rathbone, the Common Sense Society, and the Societé des Droits des Hommes were entirely my own inventions, and not to be blamed on anyone else.