Niccolò and Maffeo Polo

The brothers went into business before Marco's birth, established trading posts in Constantinople, Sudak in Crimea, and in a western part of the Mongol Empire in Asia.

[2][nb 4] The two brothers lived in the Venetian quarter of Constantinople, where they enjoyed diplomatic immunity, political chances and tax relief because of their country's role in establishing the Latin Empire in the Fourth Crusade of 1204.

[citation needed] Later, they moved east and crossed the Tigris River, and walked 17 days through the northern end of the Arabian desert where they did not encounter any towns or villages save for a few Tatar nomads with tents and livestock.

The letter also contained a paiza, a golden tablet a foot long and 3 inches (7.6 cm) wide, allowing the holder to acquire and obtain lodging, horses and food throughout Kublai Khan's dominion.

As suggested by Teobaldo Visconti, then papal legate for the realm of Egypt, in Acre for the Ninth Crusade, the two brothers returned to Venice in 1269 or 1270, waiting for the nomination of the new pope.

According to Marco's travel account, the Polos asked several times for permission to return to Europe but the Great Khan appreciated the visitors so much that he would not agree to their departure.

Only in 1291 did Kublai entrust Marco with his last duty, to escort the Mongol princess Kököchin (Cocacin in Il Milione) to her betrothed, the Ilkhan Arghun.

The party traveled by sea, departing from the southern port city of Quanzhou and sailing to Sumatra, and then to Persia via Sri Lanka and India.