In 1266, Marco Polo’s father and uncle meet Kublai Khan in Dadu (present day Beijing, China). Kublai Khan asks them to deliver a letter to the Pope and requests that they return with 100 Christians acquainted with the Seven Arts (grammar, rhetoric, logic, geometry, arithmetic, music and astronomy) plus oil of the lamp in Jerusalem. In 1271, Marco Polo embarks with his father and uncle to visit Kublai Khan, finally arriving there around 1275 delivering the sacred oil from Jerusalem and letters from the Pope. Image: Marco Polo in Tartar costume (18th century; image by Grevembrock - Scanné de Coureurs des mers, Poivre d'Arvor., Public Domain).