Alonso III Fonseca

Alonso III Fonseca (Santiago de Compostela, 1475–1534) was a Galician archbishop and politician. He was archbishop of Santiago de Compostela from 1507, and archbishop of Toledo from 1523. He was a major supporter of the University of Santiago de Compostela. He was the son of the archbishop Alonso II Fonseca (es) and Alonso II's concubine María de Ulloa.

His older brother was Diego II de Acevedo, first Count of Andrade. They had different surnames because a younger son (i.e. Alonso III Fonseca) would take the surname of his father (“Fonseca”) and the older son would take the name of his grandmother (the mother of his father the archbishop), which was “Acevedo.”