First known use of the word assassin

The earliest known literary use of the word assassination in English according the the Oxford English Dictionary is in Macabeth by William Shakespeare in 1605. However the Assassins were known about and warned against long before that. The Assassins first appear, according to Bernard Lewis in his book “The Assassins”, in the chronicles of the crusades, where it is the name for members of a sect in the Levant led by an mysterious figure known as the Old Man of the Mountains. One early mention of the sect, according to Lewis, is in a report from an envoy sent to Egypt and Syria by the emperor Frederick Barbarossa in 1175. In 1192, the first crusader to fall victim to them was Conrad of Montferrat king of the Latin kingdom of Jerusalem. Another early warning about the sect, which became known as the Assassins, was in 1332 in a treatise by a German priest called Brocardus prepared for King Philip VI of France, who was planning a new crusade to recapture the lost holy places of Christendom. Brocardus warns that they hire themselves out for murder and do not worry about life or their own salvation.