By 1291, Marco Polo had, by his own account, been in the service of Kublai Khan, the Mongol Emperor of China, for over sixteen years. In his role, he had proved so useful that the Emperor was reluctant to allow him leave to return to Europe. However, a message arrived in Khanbaliq from Arghun, the ruler of the Ikhanate (approximately the area of ancient Persia or modern Iran), asking the Emperor to send him a princess to replace his dead wife. Kublai Khan selected a seventeen year-old girl called Cogatin (whose name is spelled many different ways in different sources), and commanded Marco Polo to accompany her to Persia, allowing him to make the journey West.

The veracity of Marco Polo's travels has often been questioned, with some skeptics refusing to believe that he ever went to China at all. His last mission, escorting the Princess Cogatin to Persia, is one of the most compelling pieces of evidence we have of the truth of his account. His detailed account of this important embassy is corroborated by both Chinese and Persian sources. Unfortunately, by the time Marco Polo and Cogatin reached Persia, Arghun Khan was already dead. The mission still served its purpose for Marco Polo, allowing him to leave China and return to Europe.