After spending a year crossing this desert, Marco Polo reached Tcha-tcheou, in the province of Tangaut, a town built on the western limits of the Chinese empire. There are but few merchants here, the greater part of the population being agricultural. The custom that seems to have struck him the most in the province of Tangaut, was that of burning their dead only on a day fixed by the astrologers; "all the time that the dead remain in their houses, the relations stay there with them, preparing a place at each meal as well as providing both food and drink for the corpse, as though it were still alive." Marco Polo and his companions made an excursion to the north-east, to the city of Amil, going on as far as Ginchintalas, a town inhabited by idolaters, Mahometans, and Nestorian Christians, whose situation is disputed. From this town Marco Polo returned to Tcha-tcheou, and went eastward across Tangaut, by the town of So-ceu, over a tract of country particularly favourable to the cultivation of rhubarb, and by Kanpiceon, the Khan-tcheou of the Chinese, then the capital of the province of Tangaut, an important town, whose numerous chiefs are idolaters and polygamists. The three Venetians remained a year in this large city; it is easy to understand, from their long halts and deviations, why they required three years for their journey across Central Asia. They left Khan-tcheou, and after riding for twelve days they reached the borders of a sandy desert, and entered the city of Etzina. This was another detour, as it lay directly north of their route, but they wished to visit Kara-Korum, the celebrated capital of Tartary, where Rubruquis had been in 1254. Marco Polo was certainly an explorer by nature; fatigue was nothing to him if he had any geographical studies to complete, which is proved by his spending forty days crossing an uninhabited desert without vegetation, in order to reach the Tartar town. When he arrived there, he found a city measuring three miles in circumference, which had been for a long time the capital of the Empire, before it was conquered by Gengis-Khan, the grandfather of the reigning emperor. Here Marco Polo makes an historical digression, in which he gives an account of the wars of the Tartar chiefs against the famous Prester John who held all this part of the country under his dominion.