Bayan of the Baarin (1236–January 11, 1295), also known as "Bayan chingsang" (Mongolian: Баян, Chinese: 伯顔丞相; pinyin: Bàyán chéngxiàng) or, to Marco Polo, as "Bayan Hundred Eyes" (probably from a misunderstanding of Chinese: 百眼; pinyin: Bǎiyǎn), was a Mongol general. He commanded the army of Kublai Khan against the Song Dynasty (960–1279) of China, ushering in the Song collapse and the conquest by the Yuan Dynasty of southern China.

"Bayan" literally means "rich" in the Mongolian language.

Born a grandnephew of Nayagha, a general under Genghis Khan, Bayan came from the Mongol Baarin tribe. Nayagha, together with Bayan's grandfather Alagh and Alagh's and Nayagha's father Shirgügetü Ebügen, appear in the Secret History of the Mongols. However, at least one well-respected scholar presents Bayan as a Turk whose family had long served the Great Khans.

His grandfather Alagh was the viceroy in Khorazm province under the Mongol Empire. Bayan's father died during the Mongol siege of the stronghold of the Assassins (Hashshashin). While Bayan served in Persia with Hulegu's army, Kublai Khan recalled him. Kublai liked him, but he did not hold commanding rank in the Yuan army. After the success of the Battle of Xiangyang in 1273, Kublai appointed Bayan as the commander of the Yuan army and general Aju agreed the decision. Bayan married the niece of Kublai's Khatun Chabi of the Kunggirat.

Marco Polo (ⁱ/ˈmɑrkoʊ ˈpoʊloʊ/; Italian pronunciation: [ˈmarko ˈpɔːlo]; c. 1254 – January 9, 1324) was a Venetian merchant traveler from the Venetian Republic whose travels are recorded in Il Milione, a book which did much to introduce Europeans to Central Asia and China. He learned about trading whilst his father and uncle, Niccolò and Maffeo, travelled through Asia and apparently met Kublai Khan. In 1269, they returned to Venice to meet Marco for the first time. The three of them embarked on an epic journey to Asia, returning after 24 years to find Venice at war with Genoa; Marco was imprisoned, and dictated his stories to a cellmate. He was released in 1299, became a wealthy merchant, married and had three children. He died in 1324, and was buried in San Lorenzo.

Their pioneering journey inspired Christopher Columbus and others. Marco Polo's other legacies include Venice Marco Polo Airport, the Marco Polo sheep, and several books and films. He also had an influence on European cartography, leading to the introduction of the Fra Mauro map.