The Man in Black by Stanley J. Weyman

On the site of the old Palais des Tournelles, where was held the tournament in which Henry the Second was killed, Henry the Fourth built the Place Royale. You will not find it called by that name in any map of Paris of to-day; modern France, which has no history, traditions, or reverence, has carefully erased such landmarks in favour of her Grevys and Eiffels, her journalists and soap-boilers. But for all that, and though the Place Royale has now lost even its name, in the reign of the thirteenth Louis it was the centre of fashion. The Quartier du Marais, in which it stood, opposite the Ile de St. Louis, was then the Court quarter. It saw coaches come into common use among the nobility, and ruffs and primero go out, and a great many other queer things, such as Court quarters in those days looked to see.

The back stairs of a palace, however, are seldom an improving or brilliant place; or if they can be said to be brilliant at all, their brightness is of a somewhat lurid and ghastly character. The king's amusements -- very royal and natural, no doubt, and, when viewed from the proper quarter, attractive enough -- have another side; and that side is towards the back stairs. It is the same with the Court and its purlieus. They are the rough side of the cloth, the underside of the moss, the cancer under the fair linen. Secrets are no secrets there; and so it has always been. Things De Thou did not know, and Brantome only guessed at, were household words there. They in the Court under-world knew all about that mysterious disease of which Gabrielle d'Estrees died after eating a citron at Zamet's -- all, more than we know now or has ever been printed. That little prick of a knife which made the second Wednesday in May, 1610, a day memorable in history, was gossip down there a month before. Henry of Conde's death, Mazarin's marriage, D'Eon's sex, Cagliostro's birth, were no mysteries in the by-ways of the Louvre and Petit Trianon. He who wrote "Under the king's hearthstone are many cockroaches" knew his world -- a seamy, ugly, vicious, dangerous world.