Complex sentence: They have been hired by a wealthy benefactor to steal a piece of ancient Chinese pottery, which Kublai Khan had given to Marco Polo with this ceramic lamp is a map and blue resin which reveal the location of Marco Polo's lost fleet.
Split into simpler sentences: They have been hired by a wealthy benefactor to steal a piece of ancient Chinese pottery, which Kublai Khan had given to Marco Polo. Inside this ceramic lamp is a map and blue resin which reveal the location of Marco Polo's lost fleet.