 Since the 19th century, the lyrics are about migration, urbanization, love, patriotism, sociopolitics, maternal devotion, and other topics.Migration is an important part as a massive wave of Puerto Ricans migrated to the United States between the 20s and 50s.These massive migrations started after the American invasion in Puerto Rico when the economy changed from agriculturally based to industrially based, leaving many Puerto Ricans without jobs on the island.