How the Vatican destroyed the Knights Templar

One of the most iniquitous chapters in the history of the medieval church was revisited in Rome yesterday when the Vatican publisher Scrinium put on sale facsimiles of the trial of the Knights Templar order, held before Pope Clement V in 1308.

The book is unlikely to turn up in Foyles or Waterstone's: measuring 27 by 22in, printed on artificial parchment with replicas of the original papal seals, it is as close as the publishers can get to the appearance of the original document, which turned up in the Vatican's secret archives in 2001, having been mislaid for more than 300 years.

Academics and fans of Dan Brown's thrillers will be eager to get their hands on the book but it costs ¿5,900 per copy, and most of the 799 copies have already been reserved by specialist libraries. The 800th will be given to the Pope.

It ought to make uncomfortable reading for him. The Knights Templar, the order of monastic knights set up to defend Al-Aqsa Mosque in Jerusalem, seized during the First Crusade, went into decline after Christians were expelled from the Holy Land in the 13th century. King Philip IV "the Fair" of France owed the order large amounts of money and land; to avoid repaying the debt, he prevailed on Pope Clement V, based in Avignon and dependent on his good offices, to put members on trial for heresy.

The pope tried them, and while he found them guilty of immorality, the key charge of heresy was found to be false. It had been alleged that while in Jerusalem they had been in the custom of spitting on crosses, and underwent an initiation ceremony that involved kissing.

They persuaded the pope and his judges that the spitting was done to prepare themselves for the dissembling they would be obliged to practice if captured by the Saracens, while the kissing was a way of promising complete obedience. The pope accepted their arguments and absolved them of heresy. This, however, did not satisfy Philip. The pope was pressured to reverse his verdict, and the head of the order and his closest associates were burnt at the stake. The order's riches were handed to a rival knightly order, and the surviving knights melted away. It was a demonstration of the power of realpolitik to trump justice.

The order's downfall stimulated the growth of legends and fables about the order. Founded in Jerusalem by veterans of the successful First Crusade of 1096, it was a potent armed force designed to protect Christian pilgrims. When the pope gave it special status – exemption from local laws and taxes and answerable to no one but the pontiff – it soon became uniquely rich and powerful.

The order developed a way for wealthy travellers to pay for services received by leaving lands and wealth at the disposal of a Templar group in Europe.

It believed, as did the Jews, that Al-Aqsa was the site of Solomon's Temple, from which sprung the belief that many holy relics had fallen into its hands. The Turin Shroud, fragments of the Cross and the chalice used by Christ at the Last Supper – the Holy Grail – are among treasures it was popularly believed to have acquired.