As the saying goes: San Giovanni non vuole inganni!

Have you ever heard a Florentine say: “San Giovanni non vuole inganni" (Saint John doesn't allow deceit)? This saying is often used in situations where someone has tried to trick somebody else and the other person found out, or they don't believe the lie told. Where does this saying come from? As always there are several theories.A possible interpretation would be that the saying takes after the very character of the saint, an inflexible and rigorous person, who therefore did not like deceitful people and did not allow mendacity.However, the most accredited hypothesis connects the saying to the old Florentine currency, the Fiorino D'oro (Gold Florin).

The florin used to be one of the strongest currencies in Europe, states like France and England came to ask the Florentines to borrow money to cover the costs of their wars. In the mid-14th century, Florentine bankers lent King Edward III of England around 600,000 fiorini that were never returned!
It was the Arte del Cambio, one of the major guilds of Florence, which was in charge of making loans in these situations, but that also had the fundamental task of exchanging money.
This second operation involved many risks, because loads of counterfeit coins arrived in Florence all the time.
Therefore it was practice to control each coin by beating them on a marble slab, to check their value. In fact, it was possible to understand whether they were made of gold or another metal, from the sound they made when they came into contact with the marble slab. Every single coin was checked, with one exception: the gold florin. It was a circular coin with the Florentine lily engraved on one side and the image of San Giovanni, the patron saint of Florence, on the other. The effigy of St. John was quite complex and therefore difficult to forge. It was a guarantee of authenticity, if St. John was on the coin, there was no doubt, that was a coin of pure gold.There you have it, this seems to be where the famous saying “San Giovanni non vuole inganni” comes from.

The florin was once minted nearby the river, inside the Torre della Zecca, which still stands today on what is now called Lungarno della Zecca Vecchia, since the power of the Arno water was needed to operate the machinery used in the manufacture of coins.
However, the Fiorino was not the only Florentine currency, it was mainly used to make large purchases and loans: its value today would be around 150 euros! For minor purchases, the silver florin and the copper florin were instead created.
Today our florin with the effigy of San Giovanni remains a symbol of wealth and prestige. It is often found transformed into jewels, in the form of gold rings or pendants, and is given every year to personalities who have distinguished themselves, doing good for the city.