This is the 1775 Marriage of Juan Jose Sanchez Navarro and Maria Gertrudis Garcia 
who got married in what is now Vallecillo, Nuevo Leon, Mexico. They are my 5th great grandparents.

This record is very important since it mentions the names of their parents. The parents of Juan Jose Sanchez Navarro are Ignacio Sanchez Navarro and Juana Dominguez. 

The parents of Maria Gertrudis Garcia are Jose Miguel Garcia and Maria Antonia Josefa Lopez.

I am a descendant of theirs through their daughter Maria Tomasa Sanchez whom married Jose Rafael de la Garza.

This record also mentions that they were mestizos and that may be the reason that I can not find any more records past their parents.

Junio de 75 Juan Jose Sanchez con Anna Gertrudis Garcia menstizos

En tres de Junio en Setecinents, Setenta y cinco as el Br. Dn Jose Anto. de Villarreal
tente de Cura de esta Parroqa, caso, y velo in facie Eclesie en esta del Vallecillo
a Juan Jose Sanchez mestizo orijo y veci de esta jurisdiccion hijo legitimo
de Ignacio Sanchez Navarro, y Juana Josefa Dominguez a defunta.
con Anna Gertrudis Garcia mestiza orija, y veza de esta feliga. hija legitma.
de Miguel Garcia y Jsoefa Lopez todos de esta vecindad. Precedio
la informacion, y proclamas, que se leieron en esta Parroqa los dias
tres, seis, y catorce de meis proxima pasado, de no resultar impe-
dimento. Fueron testigos Ricardo Flores, Agustin Ximenes, y Juan
Jose Galvan [?] ante Rl. Y pa qe cosnte lo firmo-

Br Jose Manuel Pla[?] B. Jose Andres Villarreal

View Original at FamilySearch

If this couple is also one of your ancestors please let me know how you are related to them in the comments of this blog post.

• "México, Nuevo León, registros parroquiales, 1667-1981," database with images, FamilySearch (https://familysearch.org/ark:/61903/3:1:S3HY-61N9-2Q1?cc=1473204&wc=MCMV-R38%3A45389001%2C45389002%2C45502301 : 21 May 2014), Vallecillo > San Carlos > Matrimonios 1768-1863 > image 46 of 259; Parroquias de la Iglesia Católica, Nuevo León (Catholic Church parishes, Nuevo León).