José de Diego's birthday, known as Natalicio de José de Diego, is observed in Puerto Rico on the third Monday of April, celebrating the life of the influential poet and political leader born on April 16, 1866. This official memorial day honors de Diego, who was a prominent advocate for Puerto Rican independence from both Spain and the United States. He was a key figure in the Autonomist Party and later the Unionist Party, and he contributed significantly to Puerto Rican journalism and poetry, being recognized as "The Father of the Modern Puerto Rican Poetry Movement." De Diego's legacy includes founding the University of Puerto Rico, Mayagüez Campus, and his political activism aimed at achieving autonomy for Puerto Rico. His birthday serves as a reminder of his contributions to Puerto Rican culture and the ongoing struggle for self-governance.