In a life of ceaseless exploration, Marco Polo pushed out the borders of his narrow medieval world. Born in Venice in 1254, the young Marco Polo first met his father at age 15, when the elder Polo returned from a trading expedition to the East. The father's tales of the court of the Kublai Khan in China ignited a lifelong passion for adventure in the son. The Polos set out for China in 1271, traveling through the Middle East, across the Gobi Desert, to Khanbaliq in China. The journey took four years. Kublai Khan took a great liking to Marco Polo, employing him as a spy throughout his vast empire. Marco traveled and observed the cultures of Sumatra, Sri Lanka, and India in this capacity. His notes later became one of the world's great travel books, The Description of the World.