See study by J. L. Mecham (1927, repr. 1968).
In 1562, Ibarra headed another expedition to push farther into northwest Mexico. In particular, he was searching for the fabled golden city of Copala. He did not find the mythical treasure, but explored and conquered what is now the Mexican state of Durango. Ibarra was appointed governor of the newly formed province of Nueva Vizcaya (New Biscay) in 1562, and the following year he founded the city of Durango to be its capital.
In 1564, Ibarra, following rumors of rich mineral deposits, crossed the Sierra Madre Occidental to conquer what is now southern Sinaloa. Prospectors discovered silver veins in the new territory, and in 1565, de Ibarra founded the towns of Copala and Pánuco.
Francisco de Ibarra died on 3 June 1575 in Pánuco, Sinaloa, one of the silver-mining cities that he founded.