This started out as a Roman edifice that then had a church built on top of it, which then had a Romanic basilica built on top of that, and then a chapel was created.  (I think that’s how it goes – I just know a lot of things were built on top of one another again, like in Sicilia.)  There are also two churches built next to it – never can have enough churches in the exact some place, right?  (taken 4.4.2015)