Frustrated in his political ambitions, des Roches had little choice but to seek employment in the affairs of his see and in preparation for the crusade to which he had been pledged since 1221. His family in France had been involved in every general passage to the east since the 1090s. He himself had attempted to join the crusade to Damietta in its final months, at the very moment when his political fortunes in England began to turn sour. But Damietta fell too soon. From 1221 all crusading plans were dependent upon those of the emperor Frederick II, who had already several times delayed his sailing. In March 1223 at a conference in northern Italy he agreed to depart by June 1225. Since this deadline fell in the midst of the English political crisis, it was perhaps fortunate for des Roches that the emperor was again forced to seek postponement. Under the treaty of San Germano of July 1225, the terms of which were negotiated by the former legate Guala and carried to England by the papal nuncio Otto, Frederick committed himself, on pain of the most dire papal censure, to equip an army and to sail for the east in August 1227. Des Roches thus had several years in which to prepare for the crusade, rather than the few months of hasty mobilization he had allowed himself in 1221.