From BiblePortal Wikipedia

Guerin [1]

(Gerin or Guarin), whose surname and country are: unknown, a grand master of the order of the Hospitallers of St. John of Jerusalem, succeeded Bertrand of Taxis in 1240. At this time the Templars: and Hospitallers were divided; Thibaud VI, of Champagne, went to Palestine at the head of a crusade, and concluded a truce with the infidels after the loss of the battle of Gaza. The Templars subscribed to that truce. Richard of England followed next and sailed against Jaffa; he concluded a truce by which Jerusalem was to be surrendered. In that truce the Templars were entirely excluded. The grand master of the Hospitallers brought the treasure of the order to the patriarch of Jerusalem, to assist him in fortifying the walls of that city. But hardly had they made a few trenches, when all Palestine was invaded by the Koreishites. The grand masters of the Hospital and the Temple at Jerusalem, being almost without troops, resolved to conduct the inhabitants to Jaffa, while others refused to go, and tried to defend themselves, but were all cut down without mercy, or fell in open battle. Only twenty-six Hospitallers, thirty-three Templars, and three Teutonic knights escaped with their lives. The two grand masters of the two orders and a commander of the Teutonic knights lost their lives at the head of the army in 1243. Other historians say that they had only been made prisoners, and that Gurin died in 1244, in slavery. See Hoefer, Nouv. Biog. Generale, s.v.