Noel Estrada, a [Puerto Rican] musician and composer, joined the U.S. Army at the beginning of World War II; it was the first time that he had been away from his island, and he missed it terribly. He wrote the song “En mi viejo San Juan,” which became internationally famous and was first sung in 1943.
“En mi viejo San Juan” is a bolero song with lyrics that evoke sadness and nostalgia for Puerto Ricans who are away from their homeland. Since almost half of Puerto Ricans live abroad, this song quickly obtained the status of the second national anthem of Puerto Rico, after “La bonriqueña.” The city of San Juan adopted it as its official song.
Cf. Galván, Javier A. Culture and Customs of Puerto Rico. Culture and Customs of Latin America and the Caribbean. Westport, Conn: Greenwood Press, 2009, p. 12
By the way… a little bit off the Puerto Rican shores, this song makes me think of the traditional Mexican mariachi and ranchera song: “México lindo y querido”, written by Chucho Monge and made famous by singer Jorge Negrete. This song also evokes sadness and nostalgia for Mexicans who are away from their homeland.