For the year 1920 in my great-grandfathers Civil Guard records there is atleast one entry. The second note does not have a year in the margin so I do not know if it is for 1920 or 1921. Perhaps the transcription will give us context.
Here is the one confirmed note for 1920:
As you can see, this is typed text and thus quite clear. However, I can't make out some of the letters to the right hand side and Perfenecer comes up as an unknown word in my word processor.
This is the transcription so far:
Con motivo de la nueva distribución dada al Inxxx to por R.O.C. 30 Abril (D.O. núm. 100) pasa este ind [Individuo ?] Perfenecer al 18 Tercio causando baja en este 4 en fin de Mayo.
El Comandante Mayor
I have linked to the relevant bulletin but I am not sure which specific article in it relates to this note and why.
Translation
This is the translation based on the answer provided:
As a result of the new distribution given to the Institute by R.O.C. 30 April (D.O. no. 100), this individual became a member of the 18th Tercio and was discharged at the end of May.
The Major Commander
The "document" that we are working through has the heading 4o TERCIO and now he is moving to the 18o TERCIO. I wonder what the significance of this transition was? Does the linked bulletin provide any insight at all?
Bulletin
I tried to find a reference to the 18th Tercio and I found this on page 3 which is tied in with Cordoba: (which would also be correct):
I don't really know the significance of all those numbers etc. but I figure that my great-grandfather was one of those statistics there.