Sometimes, a mistake, even one that changes history, comes from ignorance, not stupidity or bad judgment. But even with that said, in this case, the difference between intent and ignorance does not make the consequences less disastrous.

A simple and economical decision made by the city planners of Rome may well be the most important cause for the fall of the Roman empire. The mistake happened because the magistrates who ruled the city of Rome found what appeared to be the ideal solution to a problem. That problem was how to supply water to all the buildings and fountains in the city.

As the city of Rome grew, eventually surpassing a million residents, the water problem grew acute. The majestic aqueducts, which still thrill twentieth-century tourists, could carry plenty of water from the mountains to the city. The problem was how to spread that water out among its users. A solution was found: an ideal metal that was malleable and easily made into pipes. These pipes could be made cheaply enough to allow their use all through the seven hills.

The problem was that this metal was lead. Yes, it’s the same material that requires tearing down walls in houses or apartments if a few flakes of lead-tainted paint are found there. But back then, lead looked like the perfect choice. It was relatively inexpensive (always a bureaucrat’s concern), could be easily rolled flat and then curled into pipes of all sizes, and its low melting point meant that the joints could be welded shut with nothing more than a good campfire. Lead pipes seemed the ideal solution to getting the water from the aqueducts to the people. The problem was that these same pipes were effectively poisoning the entire population of Rome. More important, they were extensively used in the palaces of the major Roman families and the emperor. The Centers for Disease Control and Prevention’s (CDC’s) description of the symptoms of lead poisoning pretty much says it all:


The effects of lead are the same whether it enters the body through breathing or swallowing. Lead can affect almost every organ and system in your body. The main target for lead toxicity is the nervous system, both in adults and children. Long-term exposure of adults can result in decreased performance in some tests that measure functions of the nervous system. It may also cause weakness in fingers, wrists, or ankles. Lead exposure also causes small increases in blood pressure, particularly in middle-aged and older people and can cause anemia. Exposure to high lead levels can severely damage the brain and kidneys in adults or children and ultimately cause death. In pregnant women, high levels of exposure to lead may cause miscarriage. High-level exposure in men can damage the organs responsible for sperm production.

Organ failure, brain damage, a lower birth rate, anemia, and weakness—quite a list. Now, when a good portion of the population of the capital of an empire suffers from mild to severe symptoms, you have a crippled population. Remember all those mad emperors from Caligula on? Drinking lead-contaminated water has to have contributed to their cognitive problems. So what appeared to be the ideal solution to a practical problem most assuredly weakened Rome and the other major Roman cities.

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