Lineage timeline
1856 · Tepatitlán, Jalisco, Mexico
Date of Birth: 1856
Location: Tepatitlán, Jalisco, Mexico
Father: Juan Martín del Campo
Mother: Petra González
Alejandro’s son’s civil registration already ties his son, himself, and his parents together in a primary source. However, we also have his own civil registration record:

Upper right entry.
En Lagos en el año del Señor de mil ochocientos cincuenta y seis a veintidós días de junio, yo el Presbítero Don Francisco Verdad, teniente de Cura, bauticé solemnemente en el baptisterio de esta Parroquia a Alejandro Jesús Francisco, de siete días de nacido en esta ciudad, hijo legítimo de Don Juan Martín y Doña Petra González, nieto por línea paterna de Don Manuel Martín y Doña Julia Romo, y por materna de Don Rafael González y Doña Florencia Lora; fueron padrinos Don Rafael Lorín y Doña Florencia González, a quienes advertí su obligación y parentesco espiritual, y para que conste firmé con el Señor Cura. Rafael Verdad.
In Lagos, in the year of Our Lord one thousand eight hundred and fifty-six, on the twenty-second day of June, I, the Presbyter Don Francisco Verdad, Assistant Curate, solemnly baptized in the baptistery of this Parish Alejandro Jesús Francisco, seven days old, born in this city, the legitimate son of Don Juan Martín and Doña Petra González, grandson on the paternal line of Don Manuel Martín and Doña Julia Romo, and on the maternal line of Don Rafael González and Doña Florencia González; the godparents were Don Rafael Lorín and Doña Florencia González, whom I advised of their obligation and spiritual kinship, and in witness thereof I signed together with the Parish Priest. Francisco Verdad.
Implied DOB: 15 June 1856 (7 day old baby on the 22nd)
Name: Alejandro Jesús Francisco
Father: Juan Martín
Mother: Petra González
Pateral Grandfather: Manuel Martín
Paternal Grandmother: Julia Romo
Materal Grandfather: Rafael González
Maternal Grandmother: Florencia Lora
You may notice del Campo is dropped here for multiple people. However, the ages and locations match, plus the earlier civil registration of Victor Martín del Campo González named the exact people and couple pair (as Alejandro's parents) with their full names, so this is just a shortening–probably more like how they used their names in real life.
Very importantly, this links all previous generations and also names Julia Romo, who is our maternal fork that gets us to Moctezuma.
Next entry: Juan Martin Romo