The Priory was founded in 1230 by
Duncan MacDougall, Lord of Argyll. The most widely believed origin of
Clan Chattan is that Clan MacDougall appointed Gillichattan Mor as the Ballie or protector of the Priory lands on their behalf. In 1308,
Robert the Bruce's campaign in the area included holding a council of local chiefs at the Priory, which is believed to have been the last Gaelic-speaking parliament in Scotland. From the early 14th century, the
Prior of Ardchattan held the chantership of
Lismore Cathedral. In April 1510 the Priory was incorporated as a cell of
Beauly Priory and may have become
Cistercian, but the evidence is slight. It was annexed to the
bishopric of the Isles in 1615. The Priory passed into the hands of Clan Campbell in the 16th century who converted the south range of the conventual buildings into a private dwelling house, and the choir and transepts of the church were used for parochial worship. The monastic church fell into disuse, except for the purpose of burial, following the erection of a new parish church in 1731–2. The priory church was then quarried for stone and is now heavily ruined. ==Priory==