In 1367 Urban had entered Rome, and one of his first acts on taking possession of the chair of St. Peter was to exhort the Genoese and Venetians to facilitate the voyage of John to the imperial city. The emperor was willing enough to go to Rome, provided that there was a reasonable chance of obtaining substantial aid. He had made submission once and was ready to do all that he could to complete the Union the pope so greatly desired, but he knew much better than the pope how difficult it would be to induce his people to accomplish the proposed task. His needs, however, were great, and the summons of the pope was urgent. Accordingly, in 1369, he ventured on the dangerous step of leaving Constantinople. He was received with every honour in the elder Rome, and made a profession of faith which satisfied the four cardinals who had been deputed to receive it. An encyclical notified the great news to all Christian princes. The pope allowed John to negotiate with English mercenaries then in Italy for service, granted him religious privileges, loaded him with presents, and requested the rulers of the states through which he had to pass on his homeward journey to receive him with the respect due to his rank. Urban at the same time addressed a letter to the Greek clergy urging them to accept the Union. John, however, found little or no material help. He left Rome in debt, and on his return to Venice, where, on his Romeward journey, he had been received in great state and promised four galleys, he was detained until he paid his debts. The emperor urged his son Andronicus, who had been appointed regent during the absence of his father, to find the means of releasing him. The son declared that as the treasury was empty and the clergy would not help, he was unable to obtain ransom. His younger son, Manuel, contrived, however, to find in Salonica sufficient money for his father’s release. Both Urban and his successor, Gregory the Eleventh, displayed a great desire to aid the empire to stem the tide of Moslem progress. Gregory in 1371 urged the kings of France and England to join with the Genoese to save the remnant of Christians in the Holy Land from the Saracens. All their efforts were fruitless.