In 1270, Jewish scholar-merchant Jacob d'Ancona embarked on a remarkable voyage from his native Italy to Zaitun, the city of light, a vast coastal metropolis in southern China. His manuscript, hidden from the world for centuries, provides a first-person insight into life in the 13th century. It describes a thriving mercantile economy, whose vigorous manufacture and lavish consumption in the shadow of the impending Mongol invasion represent the swansong of a wealthy, decadent and surprisingly modern society. Jacob d'Ancona's participation as a foreign trader in the grand civic debates shed light on the relationship of Jews and Christians and the role of the individual in society.