Fors Collegis Mercuris, "The Accidental College of Mercury", was a secret magical school for neophyte mages of the Order of Hermes. It was originally constructed outside Genoa, Italy in 1190 by mages of House Bonisagus. In 1450, under increasing pressure from assaults by the Order of Reason, the college was transported to the Horizon Realm of Mus, the invisible moon of Mercury.
The Collegis remained an important institution within the Order and a site of much research by both Hermetics and the Ahl-i-Batin. After the loss of the Ahl-i-Batin chantry on Mercury's surface, Mus became the primary location for studying the Shade Realm of Correspondence. However, in 1995 the College came under simultaneous attack by the Technocracy and the Nephandi, forcing the remaining Tradition mages to evacuate. The Hermetics established three secret Earth-based colleges for their neophytes to take its place, while the Accidental College was left to the Nephandi.