On what day was Hernan Cortes born?
That is one question no one can answer. His actual date of birth is unknown, All we know is the year, which was 1485.
Yes, they are, He can be known as Hernando, Hernan and even Fernando Cortes. Most people today know of him as Hernan Cortes. The spelling of Cortes with a z is wrong, he never spelt Cortes as Cortez during his lifetime, I can only think that this is an American spelling of the word, which seems to be taking over the whole Internet.