I recently posted (at least I think I did) some information on the Ortiz de San Pedro and the Lopez de Ayala. I might not have been very clear at that moment so I tried to clarify what I first posted:

I believe the confusion arises out of Romero de Solis, author of “Andariegos y Pobladores”, mistanking Pedro de Arevalo, son of Alonso de Arevalo and Beatriz Lopez de Ayala, with Pedro Ortiz de San Pedro, son of Juan (Ortiz) de San Pedro and Catalina Lopez (de Ayala). There is no reason why a son of the first couple would bear the last name "Ortiz de San Pedro”.

The reason he makes the mistake is that (1) Pedro Ortiz de San Pedro (whom Romero de Solis sometimes incorrectly refers to as "Pedro de Arevalo") had a brother named Gonzalo Lopez de Ayala (this Gonzalo, whom Romero de Solís refers to as "el Mozo", takes the name from his mother, Catalina Lopez "de Ayala"), and (2) Beatriz Lopez de Ayala had a son with the same name (whom Romero de Solis refers to as Gonzalo Lopez de Ayala "the elder"). Certain document Gonzalo Lopez de Ayala el Mozo refers Gonzalo Lopez de Ayala el Mozo as brother of Pero Ortiz: "según declaración de Marcos de Cárdenas, moreno libre, mayor de 40 años de edad, hallándose en casa de Diego de Monroy, hará 3 meses, al tiempo que falleció Pedro de Bobadilla, Pero Ortiz, hermano de Gonzalo López, le pidió al mercader Diego de Monroy, de su tienda, ciertas varas de bayeta y cierto tafetán, y otras cosas, que dijo eran para Gonzalo López, …", and (3) Romero de Solis assumes this Gonzalo Lopez de Ayala el Mozo the Gonzalo Lopez de Ayaña Elder, and that Pero Ortiz is his brother who indistinctly bears the name Pedro Ortiz de San Pedro or Pedro de Arevalo.

Gonzalo Lopez de Ayala el Mozo, is the one who married Juliana de Bobadilla. Jeronimo Ortiz was another brother.

I believe that Catalina Lopez (de Ayala) and Beatriz Lopez were sisters (not only because they share the family name, but because Beatriz carried on business transactions with Juan de San Pedro, who lived in Zacatecas, and, at one point, knowing that Juan had financial troubles, she even gave him extra time to pay for what he owed her). Diego Lopez de Ayala, married in 1561 to Juana Fernandez, might have been their brother (and not Pedro de Arevalo´s brother and, therefore, Beatriz's son, as Romero de Solis states, because the couple married in 1537, first child was born in 1538, the second in 1540. This Diego was granted a power of attorney by Beatriz Lopez en 1651 and no man would’ve been granted a power of attorney at age 10, assuming this Diego had been born in 1641).

In conclusion:

Catalina Lopez married Juan de San Pedro and had 3 sons, most likely born in Zacatecas: 1. Pero (Pedro) Ortiz de San Pedro, married to Maria de Esquivel and lived in Colima, Jerez and most probably in Tlaltenango. They had a daughter Cecilia “Lopez de Ayala”; 2. Gonzalo Lopez de Ayala (whom she names after her deceased brother), married to Juliana de Bobadilla and lived in Colima and Tlaltenango (where the Bobadillas were from); and 3. Jeronimo Ortiz, to whom there are references in Jerez.

Beatriz Lopez first married Alonso de Arevalo and had 2 sons: Gonzalo Lopez de Ayala and Pedro de Arevalo. Gonzalo died before her mother. Pedro is always referred to by Beatriz as "Pedro de Arevalo", not as "Pero Ortiz de San Pedro" (“... Iten digo que si pareciere yo deber alguna cosa a Alonso Miguel, que averiguado e liquidado lo que fuere, se lo pague Pedro de Arévalo, mi hijo. Iten … - “para hacer y cumplir mi ánima, digo que, si mi hijo Pedro de Arévalo lo quisiere tomar a su cargo, que no se haga almoneda dellos, ni justicia ni otra persona alguna se entremeta en ello, porque ésta es mi voluntad y ansí se lo encomiendo y le ruego que lo haga conmigo como Dios lo haga con él” - "El 10 de febrero, Pedro de Arévalo, hijo y albacea de doña Beatriz López de Ayala, y el muy reverendo …"). It seems neither of them married or had children.

I do not know anything about Maria de Esquivel, our Pedro's wife.

Regards,
Hector