The chapel was built by Giovanni Montemirabile (an italianized name for Jean de Montmirail), the bishop of Vaison in 1479 and it was dedicated to St. John the Baptist.
The chapel was built by Giovanni Montemirabile (an italianized name for Jean de Montmirail), the bishop of Vaison and a confidant of Pope Sixtus IV who rebuilt the basilica at the same time. It was dedicated to St. John the Baptist.