But Marco's curiosity was inherited; and no Venetian was ever averse to seeing strange lands and seeking out new opportunities for trade; so the Polos decided to go on and visit the Khan of central Asia or Chagatai, and perhaps make their way back to Constantinople by some unfrequented route.

They struggled over plains peopled only by tent-dwelling Tartars and their herds, until at last they reached the noble city of Bokhara.

They must have followed the line of the Oxus River, and if we reverse the marvellous description which Matthew Arnold wrote of that river's course in _Sohrab and Rustum_, we shall have a picture of the Polos' journey: But the majestic River floated on, Out of the mist and hum of that low land, Into the frosty starlight, and there moved, Rejoicing, through the hush'd Chorasmian waste Under the solitary moon; he flow'd Right for the Polar Star, past Orgunje, Brimming and bright and large: then sands begin To hem his watery march, and dam his streams, And split his currents; that for many a league The shorn and parcell'd Oxus strains along Through beds of sand and matted rushy isles-- Oxus, forgetting the bright speed he had In his high mountain cradle in Pamere, A foil'd circuitous wanderer:--till at last The long'd-for dash of waves is heard, and wide His luminous home of waters opens, bright And tranquil, from whose floor the new-bathed stars Emerge and shine upon the Aral Sea.
For three years the Polos remained at Bokhara, until one day it happened that an embassy came to the city, on its way back from the khan in Persia to the great Khan Kublai, who ruled in far-off China, and to whom all the Tartar rulers owed allegiance.

The chief ambassador was struck with the talents and charm of the brothers, who had now become proficient in the Tartar language, and persuaded them to accompany him on his journey to the presence of the Great Khan, who had never yet set eyes on a man of the West, and would, he assured them, receive them honourably.

They would not have been Venetians had they refused such an opportunity, and, taking their Venetian servants with them, they journeyed for a year with the Tartar embassy across the heart of Asia, and so reached the great Kublai Khan.