|Altar of the Seven Saints in the Kreisker Chapel, St Pol-de-Léon|
These incomers brought their Celtic language, which fused with local speech to produce Breton. Its closest links to Cornish and then Welsh reflect the origins of the migrants. The pattern of Breton speakers, mainly in the west of the peninsula (Basse Bretagne), shows the main areas of original settlement. Further east, the influence of Rome and the Roman church had been established much earlier and the language of Gallo, derived from Latin was spoken. The cathedrals of Rennes and Nantes are not part of the Tro Breiz.
The Breton saints are neither canonized nor officially recognised by the Catholic church. In many churches and chapels the local saint has been replaced by a more conventional worthy, whose origins have nothing to do with Brittany. But the vibrancy of Breton heritage and oral culture has secured an eternal role for these pioneers, celebrated still in Pardons, annual religious processions on the saint’s day. The evidence for the actual existence of most of these saints is nebulous, but there are occasion historically attested appearances, such as that of Saint Samson at the council of Paris c555.
The seven founders and their cathedrals are St Pol (St Pol-de-Léon), St Tugdual (Tréguier), St Brieuc (St Brieuc), St Malo (St Malo), St Samson (Dol-de-Bretagne), St Patern (Vannes) and St Corentin (Quimper). Of these St Patern and St Corentin are said to be natives (or first generation immigrants) of Brittany and the others to have come from Wales. Their life stories are preserved in later Vitae, hagiographies with many accounts of miracles and triumphs over the wild paganism they found on arrival.