Nebrija was born into a "hidalgo" family in Nebrixa, a town now called Lebrija in the province of Seville. His parents were Juan Martínez de Cala and Catalina de Xarana. He was the second of five children. There is some uncertainty about his date of birth. Nebrija wrote that he was born the year before the Battle of Olmedo in 1445, putting his birthday in 1444 but elsewhere he makes other references that would contradict this date. Traditionally, 1444 has been accepted as his year of birth.