The Knight Templars were formed after the first crusade to capture the holy land from the infidel. They received the foundations of the ancient Temple of Solomon upon the tallest mount in Jerusalem where they established their headquarters.
Their founder Hugh de Payens and his nine knights vowed to protect the overland path from the sea to the city of Jerusalem. For the first nine years of their existence however, they dug beneath the ancient temple, excavating an ancient network of tunnels. The Ark of the Covenant was supposed to be housed in this temple before the city was sacked by eastern invaders.
It is thought that they found some ancient knowledge in their excavations that may have come from Egypt or as some have hypothesised, Atlantis, a fabled city left only in legend. Plato speaks of the city in earnest certainty.
The knowledge was in the form of many things, but most noticeably to those in the middle ages, architecture. Gothic cathedral's began construction in designs never before seen, one of the first being Chatres.
The Templars became extremely powerful over rather a short period of time, mostly thanks to the work of the priest Bernard de Clairaux, who introduced them to the pope, whom eventually made them answerable to only him.
Upon their return to France, armed with what they had found, they grew strongly in number, gathering great amounts of gifts in lands and titles. Noblemen flocked to join the ranks of these knights who would grant their own lands to the order in the spirit of the brotherhood.
Templars devised the modern banking system. Pilgrims could deposit their funds with the Templars in Europe, then by the use of a coded chit could take money from Templar stronghold's upon the way to pay for their journey, for the way was fraught with peril. Upon arrival to the next destination point, the Templars would pay for the pilgrim's lodgings and recode the chit, making the necessary deductions.
Always the first to enter a battle and the last to leave during the bloody crusades that saw the rise and fall of the Latin Kingdoms in the east of Tripoli, Antioch and Jerusalem. The church sung their praisies and granted them many things for their service. They built many fine fortresses, some of which still exist today.
After two hundred years of occupying the holy land, they were ousted by the Saracen's who proceeded to push them all the way back to Europe, via the Mediterranean islands of Cyprus and Malta.
Upon the conclusion of the West's attempted conquest of the holy land for Christendom, the Templars still had great revenue from their lands, and less of a cost to arm knights for crusades. They were exceedingly wealthy and had more funds than any European monarch. France was in great debt especially to the Templar organisation, and its monarch, Philip grew increasingly jealous of the wealth of the Templars. He conspired with the Pope and brought many charges upon the knights, including heresy.
It is for this day Friday 13th was come to be known as unlucky, for that was the day that Philip arrested similtaneously all the Templars in France in a carefully planned operation. The Templars must have been alerted by someone however, as their fleet (which was also greater than any nation) departed from France with all their wealth stowed on board, and was never again to be seen in Europe.
After the Pope officially disbanded the Knight Templar organisation, those remaining fled principally to Scotland and Portugal, two nations who refused to accept the Pope's authority. Most of their confiscated wealth was redistributed to another religious order, the Hospitalliers of St John, thought to be linked with the Vatican.
The secrecy of the order has intrigued many, as inconclusive evidence points to holy artifacts such as the Holy Grail, and the Ark of the Covenant and whatever else they may have found under the Temple of Solomon. Treasure hunters have tunneled 200 feet deep into the recesses of Oak Island in search of what may be the final resting place of the Templar legacy. Did they discover America before Columbus (who flew the Templars red cross on his sails) and take an instrumental part in the American independence? (Most of the American leaders of the time were Masons) Did the Templars hold an ancient knowledge, and did they find powerful sacred artifacts that caused their swift rise?
There are only very many more questions to answer these questions, and I'm afraid it is most likely we shall never know.