Both my parents came from Mexico. In reading the history of Mexico I have seen that the name Bernardino was a first name in the 15th century. Cortez had about 4 crew members with the first name of Bernardino. When Cortez returned to Spain he took a few natives with him to prove he had found a new land. A priest in Spain, Fray Bernardino de Sanhagún became friendly with the captives and learned their Nahuatl language. Father Sanhagún came to Mexico about 7 years after Cortez orginally landed. While teaching the sons of the Aztec nobles father Sanhagún started to learn about the Aztec culture from advisors to the nobles. Father Sanhagún wrote a book that has been used as a reference for Pre-Columbian culture studies.
This next part is my assumption and speaking to college professors of Archeology and Pre-Columbian history, I'm told my assumptions are probably correct. It is my assumption that as Father Sanhagún converted the natives to the Catholic religion, the converts were asked to take a Christian name. They didn't know of any, so they took the Fathers name of Bernardino. Now the legend of Our Lady of Guadalupe says that the native that saw the apparition of Our Lady had a sick uncle named Juan Bernardino. Now you may not believe in the legend of Our Lady of Guadalupe, however, the fact remains that recorded history shows there was a person named Juan Bernardino living in what is now Mexico City in 1531. I'm interested any other information anyone may have on this name.