The Templars were founded in 1119 to protect waves of pilgrams traveling to the Holy Land. (Ben Birchall/PA Wire)

Cullen Murphy is the editor at large of Vanity Fair. He is the author of “God’s Jury: The Inquisition and the Making of the Modern World.” His new book “Cartoon County: My Father and His Friends in the Golden Age of Make Believe,” will be published in November.

The planning was meticulous. Signed and sealed, laden with accusation and instruction, the letters were sent by the king to local authorities throughout his realm. They were to act exactly one month later, simultaneously and at the crack of dawn — on a Friday the 13th, as it happened. The targets were unaware of what lay in store, their leader even spending time with the king and seeming to enjoy his favor. The hour came, and armed men launched their surprise, summarily carrying off hundreds to the king’s dungeons, and many ultimately to their deaths. It was a performance reminiscent of a Stalinist purge or Hitler’s Night of the Long Knives.

The year was 1307, and the month was October. The king was Philip IV of France. And his victims were all members of the order of “the Poor Fellow-Soldiers of Christ and the Temple of Jerusalem,” better known as the Knights Templar — or simply the Templars. Over a period of two centuries, this charitable and military order of Crusaders had grown in power and wealth. At a stroke, and with the acquiescence of a weakened pope, Philip destroyed the order, imprisoning its leaders and burning many at the stake. “God will avenge our death,” said James of Molay, the last Grand Master, as he faced the flames on an island in the Seine.

And, in a way, God has. The Templars live on in popular culture — from the video game “Assassin’s Creed” to Dan Brown’s “The Da Vinci Code.” Philip IV does not.

“The Templars,” by Dan Jones (Viking )

Dan Jones, the author of well-regarded histories of the Plantagenets and the Wars of the Roses, obviously gives no credence to the conspiratorial fantasies that have been spun around the Templars over the years. No, they do not guard the Ark of the Covenant or the Holy Grail, and never did. No, a surviving remnant does not protect the identities of the descendants of Jesus and Mary Magdelene. No, the order does not secretly run the world — that’s the Trilateral Commission or maybe Skull and Bones. In “The Templars,” Jones relegates this curious afterlife to an epilogue. His aim is to present a gripping historical narrative, and in this he succeeds.

The raw material is rich. Founded by a French knight in 1119, after the successful First Crusade, the Templars began with a mission to protect throngs of pilgrims now traveling to the Holy Land. The members of the order wore white robes with a distinctive red cross, embraced personal poverty and lived according to a regime codified by the great Cistercian abbot Bernard of Clairvaux. A papal charter was followed by a papal decree granting the Templars an exemption from taxes and local laws, effectively creating a transnational entity whose members could go anywhere. As Jones describes it, the order comes across as a combination of Blackwater, Goldman Sachs, Kroll International, FedEx, Fort Knox, Bechtel and, well, the Red Cross.

The financial acumen of the Templars was considerable. In the post-“Da Vinci Code” era, visitors to London often make their way to the Temple Church, between Fleet Street and the Thames, built in the mid-12th century. The circular nave — typical of Templar churches — is the oldest part of the structure and was used as a repository by English nobles and by the Crown itself. “By the 1240s,” Jones writes, “the order was providing diverse financial services to some of the richest and most powerful figures across Christendom.” The Templars “guaranteed debts, ransomed hostages and prisoners of war on credit, and could arrange very large loans — such as the one made in 1240 to Baldwin II, the emperor of Constantinople, and secured by his very own fragment of the True Cross.”

The order’s military record was mixed. In 1187, an army of Templars and others, under King Guy of Jerusalem, was surrounded and slaughtered by the sultan Saladin in his successful campaign to restore Palestine to the Muslim fold. Saladin had played his hand skillfully: stopping up wells even as he enticed the Christians farther into the searing flats; pausing long enough to allow dehydration to take its toll; then moving in for the kill. Some 200 Templars were captured, and Saladin beheaded them all.

That was an unhappy episode, but the Templars had another century of influential life in front of them, until that Friday the 13th in 1307. Philip IV was pious, paranoid, unscrupulous and mercurial — and deeply in debt to the Templars. It was all too easy to manufacture charges of heresy, blasphemy and sexual depravity: urinating on the cross, having sex on the altar — the usual allegations. The power and secretiveness of the Templars only fueled the charges. The decisive blow was struck in France, but within a few years the Templars were extinct throughout Christendom, except in the popular imagination.

“The themes of the Templar story resonate powerfully today,” Jones observes. He rightly does not pontificate about this and draws no specious parallels, but the reader can’t help recognizing familiar territory. There is the preoccupation in the West with what we now call the Middle East. Religions collide and atrocities abound. Cries of “Allahu akhbar” pierce the din of battle. The power of states is threatened, or seen to be threatened, by unaccountable forces with global tentacles. Information is unreliable and easily manipulated, allowing conspiracy theories to take root and spread.

Nothing is left of the Templars except words on parchment and ruins in stone. An older crusading order with certain similarities, the Knights Hospitaller, does still exist, after a fashion — its genetic progeny are the Knights of Malta. They have a palatial headquarters on the Aventine in Rome. They have a papal charter and enjoy quasi-sovereign status. They can issue their own passports. They maintain diplomatic relations with a hundred countries. And, like the Templars, they do not rule the world.

The Templars
The Rise and Spectacular Fall of God’s Holy Warriors

By Dan Jones

Viking. 428 pp. $30