Their journey led them through Samarcand, Cashgar, and other cities of the far East, a whole year passing before they reached the capital of the great potentate, by whom they were graciously received. Kublai asked them many questions about their country, and was very curious about the pope, to whom he in the end sent them as ambassadors, bidding them return to him with a hundred Europeans learned in the arts and sciences, for the instruction of his people. They reached Venice in 1269, after an absence of fifteen years. In 1271 they set out again for China, bearing despatches from the pope, but without the learned Europeans they were to bring. Marco, the young son of Nicolo, accompanied them on their journey, which occupied three and a half years. Kublai, though he had nearly forgotten their existence, received them as graciously as before, and was particularly pleased with young Marco, giving him a high office and employing him on important missions throughout the empire. In truth, he took so strong a fancy to his visitors that they were not suffered to leave China for years, and finally got away in 1291 only as escort to a Mongol princess who was sent as a bride to Persia. Twenty-four years had elapsed from the time they left Venice before they appeared in that city again. They were quite forgotten, but the wealth in precious stones they brought with them soon freshened the memory of their relatives, and they became the heroes of the city. Marco took part in a war then raging with Genoa, was taken prisoner, and long lay in a dungeon, where he dictated to a fellow-prisoner the story of his adventures and the wonderful things he had seen in the dominions of the Great Khan of Cathay. This was afterwards published as "Il Milione di Messer Marco Polo Veneziano," and at once gained a high reputation, which it has preserved from that day to this. Though long looked on by many as pure fable, time has proved its essential truth, and it is now regarded as the most valuable geographical work of the Middle Ages. We cannot undertake to give the diffuse narrative of Marco Polo's book, but a condensed account of a few of his statements may prove of interest, as showing some of the conditions of China in this middle period of its existence. His description of the great palace of Kublai, near his capital city of Kambalu, much the largest royal residence in the world, is of sufficient interest to be given in epitome. The palace grounds included a great park, enclosed by a wall and ditch eight miles square, with an entrance gate midway of each side. Within this great enclosure of sixty-four square miles was an open space a mile broad, in which the troops were stationed, it being bounded on the interior by a second wall six miles square. This space, twenty-eight square miles in area, held an army of more than a hundred thousand men, nearly all cavalry.