Large numbers of Britons fled west into the regions we now know as Wales and Cornwall, and very many went to Brittany. A great number of these were priests. This contributed immensely to the Christianisation of rural ‘Armorica’ (as Brittany was then called).
Brittany had different customs than those of more traditional; priests were itinerant, both the Body and the Blood of Christ were recived in communion, and women being allowed to administer the chalice. In time these practices were criticised as too ‘Irish’. What was meant that they were not Roman.
Brittany is said to have made very many saints – 300 are known
Of the itinerant evangelists seven were picked out as the Seven Founder Saints of Brittany – just as Ireland picked Twelve Apostles of Ireland.
There is a very old pilgrimage called the tour of Brittany, where the pilgrims walk around Brittany from the grave of one of the seven founder saints to another. Historically, the pilgrimage was made in one trip (a total distance of around 600 km) for all seven saints. Nowadays, however, pilgrims complete the circuit over the course of several years.
Brittany became part of France in 1532.