Additional Aztec/Mexico information.
The grand advisor to the Aztec chief several decades earlier had instituted a policy which greatly increased the enthusiasm of the surrounding tribes/cities/towns for assisting the Spaniards. Protein was always in short supply especially for a warrior people. They had turkey, fish, dogs, but nothing large like cattle. This grand advisor basically said "let us make tlaxcalla (and other places) our granery." He instituted a very systematic program of annual warfare in which thousands of captives were brought back to the capital, sacrificed by having their hearts cut out, then eaten by the citizens. I may be mistaken, but I seem to recall a number of 100,000 being the total number of Tlaxcallans killed and eaten over many years.
Two long contemporary accounts of the conquest are Cortez' "Five Letters to King Carlos V" of Spain, and the account written by one of his lieutenants Bernal Diaz. A Twentieth Century historical novel of that time is "Heart of Jade" by Salvador Madarriaga.
I spent one entire afternoon, wandering through the ruins and restorations of the old sacred city of Teotihuacan, about 30 miles outside of Mexico City (then known as Tenochtitlan). It was really a very large city, several miles along the main thoroughfare, and extending to the side a fair distance as well. Quite amazing.
I....just....ate......:-P