Complex sentence: He recorded his most famous song "Nuestro juramento" in 1956, and some years later the song's composer, Puerto Rican author Benito de Jesús, thanked him for the fame of the song.
Split into simpler sentences: He recorded his most famous song "Nuestro juramento" in 1956. Some years later the song's composer, Puerto Rican author Benito de Jesús, thanked him for the fame of the song.