 According to legend, one Carinthian noble Cacellino ("Kazelin"), a member of the Aribonids dynasty, about 1084/85 ceded his Friulian estates around Moggio to his brother-in-law Patriarch Frederick of Aquileia.Though the deed of donation has been identified as a fake, it is documented that in 1119 Frederick's successor Ulrich of Eppenstein established a Benedictine monastery at the site, dedicated to Saint Gall.By an 1185 bull of Pope Lucius III, the abbey was directly subordinate to the Holy See.