The year of foundation of Gerano is unknown; however, it is known that in 1005 it constituted a castrum.[3] In the Middle Ages, due to its strategic and economic importance, as the capital of Massa Giovenzana (replacing the more ancient Trellanum), for a while, Pope Gregory VII was interested in it, who in 1077 confirmed Gerano to be divided between the diocese of Tivoli and the abbot of Subiaco.