The brightest, whitest togas in ancient Rome all had one thing in common. They had been soaked in urine.
Rome's laundries — the fullonicae — had no soap. What they had were pots: vessels set out to collect urine from the city's public conveniences, hauled back by the jarful.
It sounds like madness. It's chemistry.
As urine ages, its urea breaks down into ammonia — still one of the best degreasers and whiteners there is. The fullers soaked the wool, worked it clean, rinsed it, and handed back togas gleaming. An empire's worth of white cloth ran on the stuff.
Which means urine had value. And in Rome, anything with value eventually met the tax collector.
In AD 69, Vespasian took the throne of an empire fresh out of civil war — with a treasury to match. He needed revenue, fast. He looked at the pots.
And he taxed them.
The vectigal urinae — the urine tax — fell on those who bought the city's urine for industry. His son Titus was appalled, and told his father that profiting from public toilets was beneath the dignity of an emperor.
The historian Suetonius records Vespasian's answer. He held a gold coin to his son's nose and asked if it smelled. "No," said Titus.
"And yet," said the emperor, "it comes from urine."
Pecunia non olet. Money doesn't stink.
The phrase outlived Titus, outlived Vespasian, outlived Rome itself — Europeans still say it, two thousand years later. And in France, public urinals came to be known as vespasiennes: the emperor's name, fixed forever to the thing he taxed.
Empires fall. Monuments crumble.
A good tax, apparently, is forever.