I have found that the surname Mendoza is probably of Spanish origen. It means frigid mountain, probably due to the region they lived in. There are stories about how some Mendozas helped the Monarchy of the time by fighting the Moors and running them out of Spain. One Mendoza came to Mexico in the 15th century and became an Archibishop, well loved by the people because of his kind nature to the natives, while most Spaniards of his time were cruel and opressive. I believe he helped establish the Guadalajara region. My husband's family is Mendoza, from his Dad's father. They came from the Sonora, Mex. region. There were other explorers who came into different areas of Mexico, while some traveled inland to explore new areas of the so-called Nueva Espana. We have not been able to establish a connection to anyone in particular.