Is not the holey grail, its a book.
Today there is still the book of Kells secured in a museum, but the book of the Templers is lost. The book of Kells is a scripture and early version of the Bible that is created so perfectly that the legend says angels guided the hands of the monks, like God guided Muhammed when he was writing the Koran.
And here we go. The treasure of the Templars was a as perfect translation of the Koran that was lost in the last battle of Jerusalem and disappeared. The Templars were on one hand side those that adopted the Arabic number system and also their investment based banking system, that learned how to build telescopes and that there was an empire way further east that was real and no Roman myth, but also the Order that murdered Moslems, burned down Mosques and plundered rich Moslem tradesmen.
The Koran describes the unbeliever as those that do not stick to any contract and that will lie and pretend for their own wealth, building up on the old Testament that warns the faithful and good hearted of those serving a demon called Mammon over God.
Since the Nazis reshaped this world in battle with Communists the same spirit and attitude that destroyed the good and faithful part of the Templers is needed to become rich in this world: Egoism and serving Mammon. Today the Good Samaritan won't have any cape to cut in half for the very poor that is starving and all build higher fences over longer tables to keep even as little as they have. Only the poor share as much as they have to gain.
The Templers, that existed past loosing Jerusalem, lost their Jihad which is first the inner fight against the bad within and than got terminated by that inner enemy uniting with an enemy form the outside.
That war was lost at the day when one of them decided to leave behind the treasure of the Templars over his own egoistic desire.
In the latest movie on the last battle of Jerusalem the last Knight takes with him the sister of the last King of Jerusalem. This last King was the head of the actual enemy within, but his sister a good wife for the heroic and strong Knight, while taking the treasure to Rome and uniting with the good from the outside to fight the bad in the inside would have meant to continue the suffering by staying in an even more difficult war full of sacrifice, treason, disgust, mean tricks and covered betrail for possibly the rest of his live.
Until today the Koran is misinterpretated and our society full of straight forward lies as much as the Moslem world never accepted in return the first two Testaments about God and therefore has to struggle understanding the most prosaic and mystic part themselves that is constantly referring to the first two and its characters.
Therefore, the snake keeps selling apples successfully.