Alexandre Dumas, regarded by many as the greatest historical novelist of all time, initially made his name — and the first of several fortunes — as a playwright. When in the 1840s, he turned to producing fiction, the resulting novels naturally drew on their author’s flair for both dialogue and scenes of thrilling melodrama. Yet just as Balzac aimed to present contemporary society in his fictional “Comédie Humaine,” so Dumas even more ambitiously planned to romanticize all of French history, especially that of the 17th century and the Napoleonic era. Over the next 20 years, with the help of several different collaborators, he brought out some of the world’s longest and most-beloved novels, notably the cloak-and-sword swashbuckler “The Three Musketeers,” and that unforgettable classic of revenge, “The Count of Monte Cristo.”

Often derived from memoirs and period documents, Dumas’s books, including “The Red Sphinx,” almost always emphasized political intrigue, court scandal, duels, battles, sex and the underside of history. Little wonder that their author was nicknamed “the king of romance” or that a roundtable of his loyal followers would include not only Jules Verne and Arthur Conan Doyle but also George Macdonald Fraser and George R.R. Martin.

"The Red Sphinx: A Sequel to The Three Musketeers," by Alexandre Dumas (Pegasus)

Originally called “The Comte de Moret,” “The Red Sphinx” first appeared during 1865 in Les Nouvelles, but it was never quite completed after the magazine folded. For this handsome new edition — the work’s first translator since a wretched 19th-century version — Lawrence Ellsworth appends a related novella titled “The Dove,” which brings the adventures of the Comte de Moret and his beloved Isabelle de Lautrec to a dramatic, nick-of-time close.

Yet the Red Sphinx himself, as the historian Michelet dubbed Cardinal Richelieu, wholly dominates the book’s 800-plus pages. The action begins in December 1628, shortly after the French victory at La Rochelle chronicled in “The Three Musketeers.” A mysterious cloaked hunchback tries to hire a down-on-his luck swordsman named Latil to murder the Comte de Moret. That young man, the illegitimate son of the late Henri IV, has just arrived in Paris from Italy, bearing secret letters for Marie de Medici, Anne of Austria and Gaston, the duc d’Orleans, respectively the queen mother, the queen and King Louis XIII’s brother (and would-be successor). When Latil refuses to be an assassin, a quarrel develops, the hunchback’s three companions join the fray and the swordsman is left for dead.

After sudden bloodshed, Dumas quickly shifts the action to an elegant soiree where we are introduced to almost too many celebrated figures of French history, including the future playwright Pierre Corneille. Dumas, a ladies’ man himself, lingers over feminine beauty: Of Madame de Montpensier, he writes simply that “No one whose heart she stole ever recovered it.” He can be equally aphoristic when describing royalty: “Like all those of melancholy disposition, Louis XIII was a habitual liar.”

For years now, Cardinal Richelieu has been thwarting Queen Marie and Queen Anne, who have regularly conspired against France on behalf of their families in Italy, Spain and Austria. If the king were to die, Richelieu knows he would be at the mercy of these heartless enemies “and, within twenty-four hours of the death of the king, would be hanged.” Through his extensive spy network, the cardinal has picked up hints of yet another scheme to replace the sickly and homosexual Louis with his odious brother Gaston. One strategy would require Queen Anne to become pregnant, another the seduction of the virginal Isabelle de Lautrec.

From the start, Dumas presents Richelieu as a man of cool analytic intelligence, who is nonetheless devoted to France and beloved by those who serve him, including his next-door neighbor, the courtesan Marion Delorme. Like a modern spy master, the cardinal seeks data about everything happening in Europe. In some of Dumas’ best chapters, Richelieu even acts as a detective, trying to crack a cold case: Who actually planned the assassination of Henri IV? The search for information gradually leads him to the dark secret of the Convent of Repentant Daughters.

The author and translator Lawrence Ellsworth (Nina Harwick)

Since so much of the pleasure of this novel involves its slowly unfolding plot, I won’t say too much more. But there are scenes of farcical comedy (usually involving the cardinal’s servants), France nearly topples because of a peevish boy-favorite of the king, two old enemies sword-fight while seated in sedan chairs, and young love blossoms. To deliver his letter for the queen, the Comte de Moret had been guided through a darkened room by a young woman, whose face he never saw. Only much later at an elegant party does he learn her identity. He immediately approaches the blushing Isabelle de Lautrec and quietly declares:

“Mademoiselle, please know that there is in the world a man who, the night he met you without even glimpsing you, vowed to be yours through life and death — and tonight, after seeing you, he renews that oath. This man is the Comte de Moret.”

In the final third of this continually enjoyable novel, the action moves to the battlefield, as the armies of France enter Italy. Here several guerrilla operations behind the lines should thrill even fans of Bernard Cornwell. Here, too, Richelieu encounters a young papal officer named Mazarino Mazarini, who will eventually become a French citizen and ultimately Richelieu’s successor, Cardinal Mazarin.

So, en garde! In Lawrence Ellsworth’s excellent, compulsively readable translation, “The Red Sphinx” is just the book to see you through the January doldrums. And maybe those of February, too.

Michael Dirda reviews books on Thursday in Style.

On Sunday, Jan. 29, at 1 p.m., Lawrence Ellsworth will be at Politics & Prose, 5015 Connecticut Ave. NW.

the red sphinx
A Sequel to “The Three Musketeers”

By Alexandre Dumas

Translated from the French by Lawrence Ellsworth

Pegasus. 807 pp. $26.95