Gennadius of Astorga was a 9th-century Spanish Benedictine monk, hermit, and bishop who served the see of Astorga from 899 to 920. Born in El Bierzo around 850, he was a significant figure in the Kingdom of Leon. He is remembered for establishing various monasteries in the El Bierzo region and for his role in the development of Mozarabic art. During periods of penance, he lived in the Caves of San Genadio alongside other priests.