Despite the cooperation between the Mongols and their Christian subjects in Antioch, other Christians in the Levant regarded the Mongol approach with unease. Jacques Pantaléon, the Patriarch of Jerusalem, saw the Mongols as a clear threat, and had written to the Pope to warn him about them in 1256. The Franks did, however, send the Dominican David of Ashby to the court of Hulagu in 1260. In Sidon, Julian Grenier, Lord of Sidon and Beaufort, described by his contemporaries as irresponsible and light-headed, took an opportunity to raid and plunder the area of the Beqaa Valley in Mongol territory. One of the Mongols killed was Kitbuqa's nephew, and in retaliation, Kitbuqa raided the city of Sidon. These events added to the level of distrust between the Mongols and the Crusader forces, whose own center of power was now in the coastal city of Acre.