http://www.britishmuseum.org/research/r ... skull.aspx
Kunz claims that the skull was brought from Mexico by a Spanish officer before the French occupation (1. See references at the bottom of the page). It was sold to an English collector and acquired at his death by Eugène Boban, a French antiquities dealer, later becoming the property of Tiffany and Co.
At that time human skulls and skull imagery were known to have featured in Aztec art and iconography in Mexico when first contact with the Spanish was made in AD 1519. They were worked by Aztec, Mixtec and even Maya lapidaries, and a human skull covered with turquoise and lignite mosaic is displayed in Room 27: Mexico of the British Museum (2).