Niccolò and Maffeo were Marco Polo's father and uncle, and left as merchants one year before Marco was born. Niccolò finally made it back to Venice in 1269 and met his son when Marco was 15. Two years later, the three of them set sail for Acre to pick up items for Kublai Khan, the powerful ruler of Mongol.
After many hardships, the three finally made it to Kublai Khan's palace. Marco Polo was taken into his court and sent to many different places. Eventually, after a final mission of delivering a princess to her to-be husband (who turned out to be dead) the Polos made it back home to Venice in 1295.
After being captured in battle by Genoa, Marco Polo spent his time in prison writing a book with Arthurian adventure writer Rustichello of Pisa about all of his travels and adventures. He called it "Description of the World", later called "The Travels of Marco Polo".