Painted by Caravaggio in 1598, Marthe et Marie-Madeleine shows the conversion of Marie-Madeleine, leaving the delights of carnal seduction for the modest life advocated by her sister. In this boudoir, before us, an ivory comb with a broken tooth calls to mind the brevity of human beauty. But another question arises: how did this piece of ivory come to be in a 16th-century Roman interior?

This object, which undoubtedly came from an elephant tusk brought by Portuguese merchants from the West coast of Africa, bears the traces of little-known history, that of the age-old supply of ivory to Europe. Mingling climatic transformations and variations in international trade, it lifts the veil on uninterrupted, ever-changing commerce that takes us from the far reaches of Greenland to the ports of Mozambique.

This comb tells us of a world in which Europe, contrary to conventional stories, is not and perhaps never was the "centre" of the world.