Manuel Dionysios Díaz Martínez (1874–1929) was a Cuban fencer who competed in the 1904 Summer Olympics in St. Louis. He was born in Havana and died in Rochester, New York.Javier Ibáñez Díaz is a boxer who competes for Bulgaria.
I have two other possible interpretations for Díaz: A) "Diez" means "ten" in Spanish. It would have denoted a person who was the tenth child in a family. B) "Dies" means "days" in Latin. This probably indicated that the bearer of the surname made clocks or other devices which told the time.