I can imagine a discussion between Marco Polo and the writer, Rustichello. Marco announces he will now describe the most enormous city he ever saw. Rustichello translates the Venetian monologue into courtly Franco-Italian. As he comes to the end of his description of a market district filled with more people than he had ever seen in one place, Marco reaches for the notes he saved from his travels. He dictates numbers that Rustichello embeds in the description of how the city operates. It takes the form of a “word-problem,” the kind of narrative arithmetic we all once faced in elementary school:

If we solve the arithmetic in his word-problem, we get the following result. Forty-three carts times 223 pounds is 9,589 pounds of pepper. That is 153,424 ounces or 4,349,497 grams in modern measure. If we assume that a citizen of Kinsai consumed three grams of pepper each day, the forty-three cart-loads are feeding 1,449,832 people.

Marco Polo is much better at arithmetic than he is at historical narrative. He does not compare or contrast the grandeur of Kublai Khan’s Cathay with the former grandeur of Imperial Rome or Constantinople. He is an historical illiterate relying entirely on oral tradition. His account of Asian history is limited to the stories that he hears about the places in his normal Asian world. And these stories are further limited by decisions of the writer and teller as to which tales were worth telling.

Yet the stories he tells have proven over the centuries to be the starting point for countless European readers to fill in the gaps. The “true” historical narrative is a modern phenomenon. Our current sense of truth includes many things that Marco Polo did not care about.

He is an historical illiterate relying entirely on oral tradition. His account of Asian history is limited to the stories that he hears about the places in his normal Asian world.

When I read The Travels as an adult, I was hoping to learn who the Mongols really were from a man who knew them. The mix of references I had in my head at the time produced a puzzling question. Why did Genghis Khan appear to be “a man of great ability and wisdom” to Marco Polo, and a figure of destruction to others?

Marco Polo’s audience lived in a world circumscribed by the Mediterranean and North Atlantic. They knew as little about the nomads of Central Asia as they did about any people beyond those shores. Tartaros, the common Latin name for the steppe lands in thirteenth century Europe, came from a Greek term for the place in Hades where the Titans were imprisoned, and so he calls the people to the east of Black Sea Tartars. The way Marco describes this region is methodical, entertaining and marvelously incomplete.

After the Prologue and a description of Armenia and Persia, the reader is drawn on an imaginary journey to the east-north-east. We are told of a great desert, difficult to cross, consisting “entirely of mountains and sand and valleys.” Perhaps he is describing what is now Xinjiang in western China. We are told about the Tanghut and Uighur populations, cultures that still survive in this region of contemporary China. The people are described as a mixed population of idolaters (in this case we can surmise he was describing Buddhists), Muslims and Nestorian Christians. Marco entertains the reader by describing their strange marriage and funeral practices, their agricultural production and their centers of learning devoted to liberal arts. His description ends with an enigmatic detail: