Nicolo and Matteo remained a year in the Mongolian camp, but a war breaking out at this time between Barkai, and Houlagou, the conqueror of Persia, the two brothers, not wishing to be in the midst of a country where war was being waged, went to Bokhara, and there they remained three years. But when Barkai was vanquished and his capital taken, the partisans of Houlagou induced the two Venetians to follow them to the residence of the grand Khan of Tartary, who was sure to give them a hearty welcome. This Kublai-Khan, the fourth son of Gengis-Khan, was Emperor of China, and was then at his summer-palace in Mongolia, on the frontier of the Chinese empire. The Venetian merchants set out, and were a whole year crossing the immense extent of country lying between Bokhara and the northern limits of China. Kublai-Khan was much pleased to receive these strangers from the distant West. He feted them, and asked, with much eagerness, for any information that they could give him of what was happening in Europe, requiring details of the government of the various kings and emperors, and their methods of making war; and he then conversed at some length about the Pope and the state of the Latin Church. Matteo and Nicolo fortunately spoke the Tartar language fluently, so they could freely answer all the emperor's questions. [Illustration: Kublai-Khan's feast on the arrival of the Venetian Merchants.] It had occurred to Kublai-Khan to send messengers to the Pope; and he seized the opportunity to beg the two brothers to act as his ambassadors to his Holiness. The merchants thankfully accepted his proposal, for they foresaw that this new character would be very advantageous to them. The emperor had some charters drawn up in the Turkish language, asking the Pope to send a hundred learned men to convert his people to Christianity; then he appointed one of his barons named Cogatal to accompany them, and he charged them to bring him some oil from the sacred lamp, which is perpetually burning before the tomb of Christ at Jerusalem. The two brothers took leave of the khan, having been furnished with passports by him, which put both men and horses at their disposal throughout the empire, and in 1266 they set out on their journey. Soon the baron Cogatal fell ill, and the Venetians were obliged to leave him and continue their journey; but in spite of all the aid that had been given to them, they were three years in reaching the port of Laias, in Armenia, now known by the name of Issus. Leaving this port, they arrived at Acre in 1269, where they heard of the death of Pope Clement IV., to whom they were sent, but the legate Theobald lived in Acre and received the Venetians; learning what was the object of their mission he begged them to wait for the election of the new Pope. The brothers had been absent from their country for fifteen years, so they resolved to return to Venice, and at Negropont they embarked on board a vessel that was going direct to their native town.