The Order of St. Dumas, a former faction of the Knights Templar, are a religious sect formed during the Crusades. The Order had a falling-out with the Templars and left before the Templars were suppressed.
The Order devoted itself to the teaching of Dumas, training an Asian man named Stephen Forrest Lee to be their champion under the name "Dumas", who fought Manhunter under the name Dumas. The failure of their champion splintered the Order, allowing one extremist faction to train Azrael. Later, Mark Shaw took the Dumas identity, at the request of the main branch of the order.
The Splinter Group
A splinter group of the Order created a new champion called Azrael, a hereditary title given to the splinter order's near-superhuman enforcer and assassin. Members of the splinter order enlarged the organization's power by killing their enemies, hoarding knowledge and kidnapping some of the greatest thinkers in the world. The order also spread disinformation to ensure that the theories of the kidnapped geniuses would look so silly that nobody would miss them or examine their research. The most recent Azrael, Jean-Paul Valley, eventually destroyed the splinter group.
The Order of Purity
Another splinter group, the Order of Purity was formed, but it did not have access to the Order's financial assets or its political clout. Out of a desire to see their religion protected, the Order of Purity and its parishners constructed the Suit of Sorrows: a chain mail tabard made from the armor of one hundred violent Crusaders, worn by the champion of the Order. Whether from the blood debt of its original owners, or the psychological weight it represents, most of its wearers have gone mad. The Suit was stolen by Ra's al Ghul, who bequathed it to his daughter, who gave it to Batman.
In the wake of the Black Glove's assault on Batman, the Order of Purity stole the Suit of Sorrows from the Batcave, intending to equip a new "Azrael" to be their champion. Their intended subject, Michael Lane, has taken to the role with gusto.