15thc perception on swallowtail merlons?

[npcompl33t]

I did a bit more research into those. They were painted around 1308, by a Roman painter Cappella Brancaccio. Apparently other fescos by people in his circle / the same style are already are already on the map, like the Upper Basilica (1295–99). So it seems swallowtails are a popular motif in 1300's central italian frescos, not something naples specific.