😭😭😭 LMAO they're in Spanish too so you're probably struggling with that even more... I can make it out now since reading his letters is all I do:

Madrid / Aravaca (place in Madrid) / Colonia Domínguez (place) / 20 dic (diciembre — December) / 1926

Querido (dear) / amigo (friend) / Gregorio

It's a pain though! I'm transcribing one right now and i can't even make out the YEAR...