I believe I may have Arzac ancestors. Some of my family is from the Mexican states of Guanajuato and Michoacán, and of Basque descent. I happened across some very old papers that had been preserved in my family and they are Birth, Marriage, and Death Certificates of some Arzacs who lived in the 18th century in the Basque Country. The surnames mentioned in this papers are Arzac, Arrillaga, Berra, Casares, and Ybarburu. My Basque ancestors had the following surnames: Heredia, Infante de Chávez, Olace, Otamendi, and Ruiz de Chávez. If anyone knows of a possible connection, please feel free to e-mail me; I'd really appreciate any help.