The Romans may have traded water pipe efficiency from lead for maintaining the higher average IQ of their population.

Widespread lead pollution in the Roman Empire may have caused cognitive decline across Europe that lasted nearly two centuries, a study has found.

The intelligence quotient (IQ) of an average resident of the ancient civilization is likely to have fallen by 2.5 to 3 points as a result of exposure to the toxic metal, according to the paper, published in the Proceedings of the National Academy of Sciences on Monday.

Scientists, who studied chemicals contained in ice cores extracted in Greenland, said they found that lead pollution in the Roman Empire rose sharply after 15 BC and remained high until the decline of the Pax Romana, a stretch of peace and prosperity that ended in AD180.

2,000 years from now, researchers may find evidence of the fake vaccines and other poisons that helped do something similar to Murikan IQs. The Yankee decline is more pronounced, already, than just 2 or 3 points due to essentially convincing Americans with brains not to have children while simultaneously importing mentally substandard foreign invaders.