The law suit is premised on the idea that the Catholic Church misappropriated the assets of the Knights Templar when the Order was dissolved by Pope Clement V in 1307. Aside from seeking the cash, the suit also aims to have the Catholic Church restore the good name of the Knights Templar who were at the time alleged to be heretics, devil worshippers, and sodomizers.
The Order of the Knights Templar was founded in 1119 and functioned as a band of Christian warriors that protected pilgrims on their way to and from the Holy Lands, specifically Jerusalem, during the Crusades. However, the Order fell foul of the then King of France, Philip IV, who it has been alleged owed considerable sums to the Knights Templar. The accusations brought were seen as the perfect means of avoiding paying the debt and expropriating some of the Templar wealth.
One of the many conspiracy theories is that even though the Templar were dissolved as an order in 1307 they did not disappear forever. In fact, the assertion is that they went underground and continued to practice and pass down their traditions and beliefs. This has never been proven however it would seem that the group that has brought this action, Association of the Sovereign Order of the Temple of Christ, would have the courts believe that they are descended from the original Knights Templar.
The most likely cause of this suit is that the Vatican has been taking steps to rehabilitate the name of the Knights Templar. Last year the Vatican published a book, Processus Contra Templarios, that included a series of documents that were supposedly secret or if they were not secret wrongly filed away in the Vatican Library and only recently discovered. These documents include a parchment known as the Chinon parchment. The Chinon parchment shows Pope Clement V absolving the Templar of their crimes. Nevertheless, the ruling to disband the Templar remained in place.
The Templar's last Grand Master, Jacques de Molay, was burned at the stake along with many, many other Templar, the majority of whom had confessed to their "sins" under torture. The picture is of de Molay being led to the stake.
The chances of the current claimed incarnation of the Knights Templar are not likely to succeed in this claim unless they can furnish some irrefutable proof that they are in fact directly descended from the original Knights Templar. Most pundits believe that this is just not going to happen. Yet, it makes for fun and educational reading.