With apologies for not doing this yesterday…..

Maguelone is the site of the original cathedral, built way before the town of Montpellier. Although the current building dates from the 10th – 12th C, archaeologists have found Roman and Visigothic remains. See https://en.m.wikipedia.org/wiki/Maguelone_Cathedral for the rest of the history.

It is built on an island between the Mediterranean and the salt flats and lagoons.

After the archbishop moved to Montpellier in the 16thC, the church fell into ruin. It has now been restored and reconsecrated. It is run by a charity.