Empire in what are now the states of Michoacán and Jalisco. 

Their tradition of copper work originated mysteriously over
1000 years ago. Some theories connect its origins with the
appearance of Quetzalcoatl, the feathered serpent, a harbinger
of peace and culture. Copper religious items, such as bells, first appeared and spread with his cults throughout Mexico. Other theories compare the techniques for working the copper which appeared suddenly and without evidence of development.

The Purépecha developed some techniques for extracting
copper from rock as well as techniques for shaping it. The
working of the metal had advanced enough that it was used for utilitarian objects as well as ornamental and religious ones. The Purépecha made a number of objects from the metal including axes, boxes, fish hooks, knives, small bells, necklaces, bracelets and earrings. Copper was first worked by cold hammering but as copper loses elasticity as it is worked this way, heating was soon discovered to recondition it. The creation of objects by casting was not common for copper but was used to make small delicate objects such as bells.