Jerez

Does anyone know if Jerez was considered a Villa? I have a document from 1718 that states my ancestor was a native of La Villa de Jerez, however his father it states is a native of La Villa de Conil (which is questionable depending on who is interpreting the acta they seem to think it states Leon). Most of the people realated to my line think that it is the Jerez in Cadiz Spain. My Vialpando line originated New Mexico with the Vargas expedition, however the records are conflicting if it is Jerez, Nueva Espana or Jerez de la Frontera Spain also if its the Villa de Leon, Zacatecas or Villa de Conil, Spain. Anyone know where I might start to look for records late 1600's early 1700's for Jerez in Mexico.
Thank you...