Complex sentence: In 1579, Juan Ponce de León II became the first Puerto Rican to assume, temporarily, the governorship of Puerto Rico until the arrival of Jerónimo De Agüero Campuzano, who assumed the governorship of the island that same year.
Split into simpler sentences: In 1579, Juan Ponce de León II became the first Puerto Rican to assume, temporarily, the governorship of Puerto Rico. He served until the arrival of Jerónimo De Agüero Campuzano, who assumed the governorship of the island that same year.