According to historians, the foundation goes further back, to the Longobards
and the Monastery of St. Savior (Salvatoris) at Monte Amiata. It is possible
that the Abbey of Sant'Antimo was constructed on the site of a Roman villa
and it is known with certainty that in the 4th and 5th centuries the village of
Castelnuovo dell'Abate, on the hills nearby, was an important inhabited centre,
endowed with a parish.