In the second half of the 13th century, Eurasia lived under the overland security — the 'Pax Mongolica' — provided by the empire Genghis Khan founded and his successors expanded. The Silk Road was active again; merchants could move from the Mediterranean to the Pacific along a single political corridor. The Polos, a Venetian merchant family, were not the first Europeans to use this corridor, but they became the best known because of the book that came out of their travels.

Niccolò and Maffeo Polo had already met Kublai Khan once and returned carrying a letter from him. In 1271 they set out again, this time taking the young Marco. Travelling through Anatolia, Persia, the Pamirs, and the Taklamakan Desert, they reached Kublai's summer capital of Shangdu (Xanadu). According to Marco's account, Kublai kept him at court and employed him on various missions; the family remained in China and the surrounding regions for some seventeen years. They returned in 1295 by sea, escorting a Mongol princess via Sumatra and India back to Venice.

The book was compiled in Old French in 1298 by Rustichello of Pisa, a writer of romances whom Marco met in a Genoese prison. Circulating as Il Milione or Devisement du monde, it spread information that was extraordinary for Europe: China's paper money, postal system, use of coal, cities of a million inhabitants, the islands of the Indian Ocean. Two centuries later Christopher Columbus would sail the Atlantic with his own copy, its margins covered in notes; Polo's East was part of Europe's geographical imagination.

The historical accuracy of this journey has long been debated. Mongol and Chinese records contain no mention of a 'Marco Polo'; Marco himself fails to mention some conspicuous Chinese features — tea, the Great Wall, foot binding. A group of historians has argued that much of the book may rest on second-hand reports. Against this, many of the place names, distances, fiscal arrangements, and Yuan court details in the book have been independently confirmed. The current consensus is that Marco Polo did travel to the East, but that his account is interlaced with exaggeration, literary embellishment, and hearsay.