Q: The event that led to the Spanish taking control of copper production began in what year?  
Traditional copper work in Mexico:  After the Spanish conquest of the Aztec Empire, the Spanish took control of copper production, introducing European techniques but still needed indigenous labor. Spanish conquest of the Aztec Empire: The Spanish conquest of the Aztec Empire, beginning in February 1519, was one of the most significant events in the Spanish colonization of the Americas.
1519