Neglecting his promise to lead a crusade, Frederick was occupied until 1225 in restoring order in Sicily. The island was seething with disorder, but by stern and sometimes cruel measures the emperor suppressed the anarchy of the barons, curbed the power of the cities, and subdued the rebellious Saracens, many of whom, transferred to the mainland and settled at Nocera, afterwards rendered him valuable military service. Meanwhile the crusade was postponed again and again; until under a threat of excommunication, after the fall of Damietta in 1221, Frederick definitely undertook by a treaty made at San Germano in 1225 to set out in August 1227 or to submit to this penalty. His own interests turned more strongly to the East, when on the 9th of November 1225, after having been a widower since 1222, he married Iolande (Yolande or Isabella), daughter of John, count of Brienne, titular king of Jerusalem. John appears to have expected that this alliance would restore him to his kingdom, but his hopes were dashed to the ground when Frederick himself assumed the title of king of Jerusalem. The emperor's next step was an attempt to restore the imperial authority in northern Italy, and for the purpose a diet was called at Cremona. But the cities, watchful and suspicious, renewed the Lombard league and took up a hostile attitude. Frederick's reply was to annul the treaty of Constance and place the cities under the imperial ban; but he was forced by lack of military strength to accept the mediation of Pope Honorius and the maintenance of the _status quo_.