There are three ports in Spain that were there during XVI period:

Puerto San Sebastian:

Puerto Santander:

There are three ports in Spain that were there during XVI period:

Puerto San Sebastian:

Puerto Santander:

Puerto Sevilla:

Included are the three pictures. Most of the spanish explorers that arrived to Zacatecas were from the Basque region from “Gipuzkoa” such as Francisco Ibarra, etc.

http://en.wikipedia.org/wiki/Gipuzkoa

The ports of San Sebastian and Santander are located in the northern side of Spain near the Basque region. So I wonder if that is where they embarked rather than Sevilla which is at the very south side of Spain.