The Military and Hospitaller Order of St. Lazarus of Jerusalem— OSLJ— is an order of chivalry which originated in a leper hospital founded by Knights Hospitaller in the twelfth century by the crusaders of the Latin Kingdom of Jerusalem. The Order of Saint Lazarus is one of the most ancient of the European orders of chivalry. It was originally established to treat the virulent disease of leprosy, its knights originally being lepers themselves. It is one of the less-known and less-documented orders.