According to tradition, in 781 Charlemagne was returning from Rome along
the Via Francigena. While camped near Monte Amiata, many in his court
and army were struck down by plague. During the night, an angel recommended
him make an infusion of aspecial grass and wine and have it drunk by the soldiers.
He did this and the army was cured. The grass is known to this day as "Carolina".
In return for an end to this scourge, the Emperor promised to found the abbey
of Sant' 'Antimo.