Beware the gnomons!
Adjacent to the fountain is a small church. It's one of the ones like those I encountered at Quintodecimo (see my Aquasanta pages). It's on a more personal level than the grandiose ones you find in every travel brochure. No finely carved facade with stories from the ages, just a barely visible sundial and meridian indicator.
No Michaelangelo sculptures inside, just simple artifacts, something you feel comfortable with, not overwhelmed by. "The sun is the greatest clock in the world." Thus spake Voltaire. Gnomonists have heeded his words and so it is that we find the art of horology visible today. For the uninitiated I'm talking about the recording of time on a flat surface.
Each gnomon (from the Greek for the word for pointer or indicator) in the northern hemisphere must point towards the North Star and its axis be parallel to the north-south lines of longitude.
The dial's face is first traced then frescoed onto whitewashed plaster using natural pigments, such as black from calcinated bone, yellow from ochre, red from ferrous oxide, browns from burnt sienna and green from oxidized chrome.
Symbolic representations vary from place to place, reflecting religious beliefs and ancestral interests. You might find stars, horns of plenty, T-squares and compasses (instruments evoking the Great Architect of the universe), fleurs-de-lis (homage to the king), eagles, peacocks or tropical birds.
I saw my first one in Prague but the best place if you're a fan is the south of France.
They may have witty motifs on them such as "Vita fugit sicut umbra" - life flees like a shadow!
Their presence on churches a hint to the faithful that God himself was the author and master of time.
Sadly, this one is in need of a makeover.