In 1271 a group of Viennese merchants, including the elder Polo men, voyaged eastward. 15 years later, at a time when life expectancy was under 40, they returned, having met Muslims, Buddhists, Hindus and the Kublai Kahn, the founder of the Mongol-led Yuan Dynasty of China.
At this point in history Europe had no direct communications with the East, other than the missionaries who bumbled about trying to convert the heathens. The Mongols were a terrifying, demonic prospect, whose empire was expanding across Central Asia, China and Persia and was at Western borders by the 13th Century. The opportunistic Viennese merchants wanted to make contact and secure trade and great wealth with Islam. A second voyage set out for Constantinople and beyond, this time including the young Marco Polo, with the aim of completing a promised mission to the great Kahn bringing him oil and knowledge from the West; the journey to reach him took three years with Marco paying attention.
The Kahn, who consolidating his vast kingdom, was impressed by Marco's observations from the lands he had journeyed and asked MP to cross his Mongolian Empire and report back his findings. MP did so, using Kahn's seal to allow him him passage and protection from the conflicting Mongolian warlords. He returned 17 years later - Kahn received him as one of his own.
MP's writings were published in the 14th Century and were a sensation across Europe. A discussion continues to this day whether Marco Polo was a fictional character created by the publisher, yet the descriptive detail of the writings indicate MP was almost certainly the witness.