The Order of the Knights Templar is officially suppressed. The Templar Knights had grown incredibly wealthy over the years because everyone who joins must donate all their lands and goods to the order.
This, combined with large papal donations, has ensured the Templars' financial stability. Only a few Templars fight on the battlefield; most are running the financial organization necessary to fund their military efforts. Thus the Templars have created an early form of banking and checking.
This wealth and banking leads to jealousy, not unlike that experienced by the Jews in Europe, and that leads to their downfall. King Philip the "Fair" of France and Pope Clement V accuse the Templars of atheism, sodomy, blasphemy, and more.
Templar Knights are tortured into confessing then executed in large numbers. Scholars have debated whether any charges were true, but the general consensus is that they were innocent of the accusations. They are only attacked to get access to their wealth and prevent them from ever becoming a political threat.