In praise of deduction

So here’s a vaulted ceiling I came across in the Louvre. It’s in the lower levels, where the antiquities collection is displayed. I don’t remember which antiquities - I think this bit might have been the Byzantine stuff, give or take a few thousand years.

Keen students of vaultology will notice the arches are perfectly aligned. This makes the score one all on the wandering ceiling phenomena I’m dedicating the rest of my life to.

From my observations so far, I’ve deduced that laser alignment systems were invented between 1270 and 1547.