Juan Castro Flores was born in Tirimol in 1908. Son of farmers, at the conclusion of high school he studied in Lugo. In February 1932 came to Portomarín for teaching. More than four decades of teaching left a deep mark on generations of neighbors. Old and new Portomarín, he always considered as their own.
Political and historical circumstances partly truncated his career. His republican sympathies prevented him from taking possession of a place that was approved in 1936 as Inspector of Primary Education. But fortunately preserved the place of teacher in Portomarín.
A former student who would later become mayor, Eloy Rodriguez, remembers him as a man "extraordinarily hardworking and honest, who brilliantly formed many generations" The same view has Manuel Castelo: "I was his student from seven to fourteen years old and I have nothing but good words. The name of Juan Castro is very important to Portomarín ". Another of his pupils at school, Genaro Somoza, stresses that what impressed him most was that Juan Castro "taught not imposing, he taught you to reason."