Shortly after the conquest of the Aztecs in 1521, the Spanish pushed west. They overpowered the Purépecha in Michoacán, converting their capital of Tzintzuntzan as a base to move further west. One reason for the push towards the Pacific was to build ships and shipping facilities in order to initiate trade with Asia. Another draw was to find more mineral wealth as the Purépecha had already developed copper working along with silver and gold.