Complex sentence: He wrote in both Galician language and Castilian, and exerted as a teacher in the localities of Amoroce and Maceda (Ourense), beginning in the Galician impoverished village atmosphere his love-affair with pedagogy, that would be the great passion of his life.
Split into simpler sentences: He wrote in both Galician and Castilian, and worked as a teacher in the areas of Amoroce and Maceda (Ourense). In the impoverished Galician village atmosphere, a love-affair with pedagogy began, which would be the great passion of his life.