I’ll be the first to admit to not being a religious person, although I can see some good reasons for it, and some dreadful excuses too.
In Arles there are good reasons.
I went to Arles with van Gogh in mind, it’s another place in Provence that inspired his paintings and the city is justifiably proud of that. But the history of Arles goes back a way, quite a long way in fact and of course religion comes into that history early on.

The tower and cloisters of St Trophime 
Part of the cloisters of St Trophime
St Trophime was reputedly the first bishop of Arles and the church that bears his name is a Romanesque style building of the 9th to 12th centuries built on the site of the original church of St Etienne, the first Christian martyr.
Cathédrale Saint-Trophime d’Arles has seen many changes, rebuilds and restorations in its time, and was only saved from total decay in 1840 when it was classified as an historic monument.
Artefacts from St Césaire (470-542) are maintained on public view in the cloisters, although you do have to open a door or two to find them. The cloisters are probably the best preserved original part of the complex, and while it does cost to visit, a day pass to the main historic parts of Arles is the best way to see a lot of history.
Oh, the Roman stuff …

Part of the Roman theatre 
The arches of the amphitheatre 

Part of the view from the tower at the amphitheatre
There’s a very impressive amphitheatre, a Roman theatre, various museums, sections of city walls and the like, sometimes with modern strcutures added around them.
And I never did get to the Fondation Vincent van Gogh …
