Britain's Mystery Schools

On schools in Britain that were (or are) not Christian Monasteries.

Sibyl of Warinsey

Old writers refer to the Witch of Iona and the Sibyl of Warinsey on the island of Guernsey. The Norse lays of Helgi also refer to hags or sibyls on the Channel islands.

Folk tradition held that the tidal island of Mont St Michel had a college of female druids who “distributed to the faithful amulets which possessed marvelous properties and arrows which never missed their mark.”
Ref : Gaels and Gauls

There is the strong possibility that mention of "crows" in many old stories is really saying "old woman/women dressed in black".

Black Madonna = Isis?

College of Theodosius / Cor Tewdws

The author of the Wiki page on College of Theodosius / Cor Tewdws starts by saying it “was a Celtic monastery and college in what is now Llantwit Major.

Next : Ancient Time-keeping