Christianity reached Gaul during the early second century AD. There is very little evidence of who the first Christians were in Gaul or how the Christian faith became established there.
It is also unknown when the first church was established at Chartres. It could have been as early as the third century AD, but there is no firm evidence of a Christian community in the town at that time. Most historians believe that the date for Christianity being established in Chartres was about AD300.
The first real evidence of Christianity in Chartres is from an ecclesiastical text dating from the fourth century AD, which mentions St Adventinus as Bishop of Chartres. We do not know if there were other bishops before him, but the fact that Chartres was mentioned shows that it was quickly established as an important Christian center. There must therefore have been a church of some size by about AD350 in Chartres.
The first church was located at the foot of the city wall built in Roman times. A church becomes a cathedral when it is the church of a bishop. Therefore, some time during the fourth century, Chartres had its [L3 202 / first cathedral.]
