The emperor Vespasian was an extremely accurate and thrifty person. He translated his traits into public life. He reformed the finances of the state, and primarily strengthened the treasure, which was heavily ruined by Caligula and Nero.
Vespasian introduced c. 70 CE. urine tax. Urine collected in public toilets was sold, among others, to tanners, wool producers or laundries; the purchaser of urine was required to pay tax on urine. Vespasian was criticized for this idea, e.g. by his own son Titus, who believed that father dealt with frivolous aspects of the economy.
When Titus found fault with him for contriving a tax upon public conveniences, he held a piece of money from the first payment to his son’s nose, asking whether its odour was offensive to him. When Titus said “No,” he replied, “Yet it comes from urine.”
Interestingly, there are popular words: Pecunia non olet, meaning “money does not stink” – words that Vespasian was to say as a reaction to criticism of his son. We do not find any confirmation for those words in ancient sources and they have certainly become simply a phrase intended to emphasize that money can be earned in any business.
Finally, it is worth adding that in France it is customary to user term “Vespasians” for public toilets for men.