The Order of the Knights Templar (Poor Knights of Christ and the Temple of Solomon) was founded in 1118 to protect Christians on pilgrimage to Jerusalem, captured from the Muslims in 1099. The Order was sanctioned by King Baldwin II of Jerusalem and he quartered the nine original knights, lead by Hugh de Payens, in the old stables at the Temple of Solomon.
For the next seven years the Order kept a very low profile, rarely venturing from the Temple, let alone protecting pilgrims on the road to the Holy Land. Some say the Knights Templar were searching for the Holy Grail, some say it was the Arc of the Covenant that they sought, but regardless of the reason the Knights were certainly not fulfilling their duties.
In 1126 Count Hugh de Champagne donated his estates to Bernard of Clairvaux (later to become Saint Bernard) to finance the building of Clairvaux Abbey then left to join the Templars in Jerusalem. Bernard felt obligated to support his benefactor and petitioned Pope Hornorius II to officially sanction the Knights Templar.
In 1139 Pope Innocent II issued the 'Omne Datum Optimum' Bull, declaring the Knights Templar to be under direct and sole control of the Pope. As such the Knights had free reign over Christendom without having to pay homage or ask permission from local ecclesiastical of secular rulers (unprecedented power for a single Order). They were authorized to have their own priests to hear confessions and issue penance, highly unusual at the time, giving rise to the first murmurs of a 'secret society'.
In 1147 the Knights Templar, their ranks now swelling with dedicated volunteers from noble and aristocratic families of Europe, were authorized to wear a red cross upon their white mantles, both a symbol of chivalry and honor and a sight to be feared by their enemies.
The Knights Templar established the first international banking service. Pilgrims not wanting to travel with large amounts of money would deposit their fortunes at any Temple (for a small fee, of course), be given a receipt and a code word they would need to claim their money at the end of their journey. The Knights Templar were the primary bankers for the Holy See and several of the European Royal Houses. Financial services offered included collecting taxes, controlling debt and administrating pension funds. They owned their own fleet of merchant ships and became successful traders of pepper and cotton, as well as transporting pilgrims between Europe and the Holy Land. Many who couldn't afford to pay up front for the passage, willed their properties to the Knights Templar as payment for transportation to and from Jerusalem.
In 1305 Phillip IV of France, also known at Phillip the Fair (in reference to his good looks rather than his people skills) seized control of the Holy See and relocated the Papacy to Avignon. Having Pope Clement V firmly and completely under his control, Phillip began to issue 'Papal' decrees. (Phillip had spent much of his reign devaluing France's currency and dropping his economy into a deep, deep hole from which there was no escape other than borrowing from the Knights Templar). He had, in fact, sought refuge at one of the Temples in France to escape a lynch mob and saw for himself the vast wealth that the Templars had at their fingertips. He resolved to have it all for himself and as Phillip controlled the French Inquisition, he wielded them like a weapon to destroy the Order. Slowly, but surely, Phillip plotted against the Order, creating a long list of heresies, crimes and accusations of blasphemy against the Knights Templar.
Friday 13th of September, 1307. The warrant for arrest and detainment of the Order and seizure of all assets was sent out, to all of Europe, weeks in advance of the date with strict orders that the warrant not be opened until dawn on the 13th. This ensured a 'surprise attack' on all Templar strongholds at the same time, eliminating the ability to send warnings out to fellow Knights. However, the Templars had already been warned by sympathetic sheriffs and clergy that the arrests were ordered and the word was spread. The 18 Templar ships that had been based at La Rochelle were gone, along with the legendary Templar Treasure, never to be seen again. When the Temples were invaded it was to find barely a handful of Knights at each location, left behind to cover the retreat of their brothers-in-arms. One of these men was Jacques de Molay, the last Grand Master of the Order.
The Grand Master and hundreds of Templar Knights were arrested and imprisoned all across Europe. The fate of those captured and held in France was horrific, more so there than anywhere else in the known world. Starvation and torture were used unsparingly to extract confessions and confirmation of Phillip's ridiculous 'list of crimes'. Many confessed to stop the torture and were gifted with a quick death, others never broke at all and died in custody. Jacques de Molay confessed under torture then recanted, earning him Phillip's wrath and he became the target of Phillip's frustration at never finding the Templar treasure.
March 18th, 1314. Jacques de Molay and several of his brothers-in-arms were slowly roasted at the stake for their 'crimes against the crown'. Legend has it that as he burned Jacques de Molay cursed the three men he held responsible for his personal agony and the persecution of his Order. Phillip the Fair, Pope Clement V and Chevalier Guillaume de Nogaret (the King's Grand Inquisitor). He said, in effect, that these three men would follow him to the grave within a year. “.. I order you to appear before the Tribunal of God. Cursed are you all. Cursed until the 13th generation.”
Pope Clement V died on April 20th, 1314 from a virulent bacterial infection, Guillaume de Nogaret was poisoned to death on April 27th, 1314 and Phillip the Fair died on November 29th, 1314 due to a fatal fall from his horse during a boar hunt.
The curse supposedly ended with the decapitation of Louis XVI, the 13th King from the Capetian Line (Phillip's descendants). One of the legends stemming from this time is that when Louis' head had fallen in to the basket, an unidentified man leapt up onto the platform, dipped his hand in the King's blood and cried “Jacques de Molay.. tu es venge!” (Jacques de Molay.. thou art avenged).
There are many stories about the fate of the Templar Knights after 1314. Some say they sailed to the New World (the Americas) and settled there, others say they turned their training to piracy, others say that they lost heart as an organization after de Molay's death and just faded away. I personally believe that a bulk of the French Knights went to Scotland where they were welcomed as brothers by Robert the Bruce, no friend to either the French King or the Papacy. There are many who believe that Knights Templar acted at the Bruce's cavalry at the Battle at Bannockburn (June, 1314), turning the tide against the English. It took another fifteen years for Scotland to win her independence, but Bannockburn was considered to be the key that unlocked the door to freedom. Legend has it that upon reading the Papal Bull ordering the arrests of all Templar Knights, Robert the Bruce used it as toilet paper.
But that, like most everything else Templar related, is speculation.