In 1271, the ruler of the enormous Mongol Empire invited Marco Polo into his service, thus began Polo's 25 years of travel to the far corners of the Mongol empire. Ages 8+ years.
In 1271, 17-year-old Marco Polo traveled from Venice to meet the great ruler of the East, Kublai Khan. When he returned 25 years later, he wrote The Book of Marco Polo.