Bringing back Juan de Moscoso y Sandoval

Hello, everybody!

I am here to bring back the Juan de Moscoso y Sandoval mystery. I have been trying to gather as much information as possible, and nothing really fits just fine. I have read that the most accepted theory is perhaps that he is son of Lope de Moscoso Osorio and Leonor de Sandoval, but that doesn't quite fit.

I read in this same forum that this could be the case, since in Nobiliario genealógico de los reyes y títulos de España (https://play.google.com/books/reader?id=Vs0WAAAAQAAJ&hl=es&pg=GBS.PA332) it is stated that they had 10 children, yet only some of them are mentioned. However, they actually are there (Gaspar, Baltasar, Melchor, Rodrigo, Antonio, Isabel, María, Catalina, Francisca and Ana), and I've come across many sources (such as http://www.royalrurikovich.com/images/genealogy/moscoso.pdf) that fully describe their lineage, without any Juan in it.

In the same document, however, we can see the house of "Vazquez de Moscoso". We must remember that, in another source that I found in this website (https://www.dropbox.com/s/5ilkq4isy5xernu/Sandoval%20L%20F%20%282004%29%20Mexticac%C3%A1n%20en%20im%C3%A1genes%20Guadalajara%2C%20Jal%20Pgs%2023%20-%2028%20NR.pdf?dl=0), there is a quick mention of Juan de Moscoso y Sandoval, son of Mateo Vasquez de Sandoval. Another user stated this makes sense, since the surname Vazquez can be found later in the tree. This is the only mention in which I've found Moscoso and Vazquez together; still, no trace of any Mateo was found.

However... yet another user posted a document (http://pares.mcu.es/ParesBusquedas20/catalogo/show/440989) where Francisco de Sandoval and Juan de Sandoval (brothers) ask to go from Alcabon to Mexico. Now, this document is really hard to read and I haven't been able to understand a lot of it, but it is from 1607 and it states that Juan is young at that point and they want to move since they have relatives who wanted them there because they are lonely. It would make sense to think of Juan de Moscoso y Sandoval at a young age at this point. This document says these guys are sons of Pedro de Sandoval and Catalina Martin.

Also, I'd like to take into account that surnames in this period are rather ambiguous and hard to trace. In my own tree I found Juan Manuel de Moscoso y Sandoval, then Moscoso disappeared for two generations (his father, Tomás, and his grandfather, Nicolás, appear everywhere I looked as just "Sandoval", and then Juan brings back "Moscoso". Furthermore, in the family of Lope and Leonor we can find a whole bunch of irregularities in last names.

My question would then be as follows: is it possible that our Juan de Moscoso y Sandoval is related to the spanish Moscoso y Sandoval family as a cousin? Perhaps some side of the Vasquez de Moscoso also got involved with the Sandoval family (again, it was not uncommon for last names to apper over and over in more than one side of families), thus birthing in some point Mateo Vazquez de Sandoval and eventually Juan?

Or, maybe Mateo Vazquez de Sandoval is the relative Francisco and Juan are coming with, thus the last names don't quite match?

There are so many dead ends and so much information that still cannot be verified with a document. However, I feel like we can get closer to solving this by making assumptions that can light up a path where we can search for further information. Also, I feel like the document of Francisco and Juan de Sandoval could be helpful if we could only understand the very cryptic handwritting.

Any help is very, very welcome. Has anyone found any helpful information?