Silver fueled the rise of the Roman Empire. But the ancient process of mining and extracting silver was also making the air thick with lead, scientists found.

Why empires fall is a question that fascinates many. But in the search for an answer, imagination can run wild. Suggestions have emerged in recent decades that attribute the rise and fall of ancient empires such as the Roman Empire to climate change and disease. This has prompted discussions over whether "536 was the worst year to be alive".

Using Arctic ice core samples, researchers estimate silver mining and smelting released enough lead during the Pax Romana to cause a 2.5- to 3-point drop in IQ

The new research adds context to a long-standing debate about the role lead pollution and poisoning may have played in the collapse of the Roman Empire. Some historians have argued that Roman elites and emperors who purportedly displayed odd,

"A 2 to 3 points lower IQ doesn't sound like much, but when you apply that to the entire European population, it's quite a lot."

Using modern evidence of lead pollution and its health effects, the international team calculates that lead exposure in the Roman golden age could have caused a population-wide drop in IQ of about 2.5 to 3 points per person. And that goes for most of the Roman Empire, including its provinces of Gaul, northwestern Africa, Iberia, and Britannia.

Atmospheric lead pollution likely caused cognitive decline among citizens of the Roman Empire, according to research published Monday in the Proceedings of the National Academy of Sciences. Researchers analyzed ice core records for an approximately thousand-year period corresponding roughly with the period from the Roman Republic through the decline of the empire,

DRI scientists analyzed Arctic ice core records to reconstruct historical atmospheric lead pollution from Ancient Rome, uncovering a link between lead exposure and cognitive decline. Lead exposure is a significant public health concern,

The mass production of silver coins in the Roman Empire had an unintended effect: spewing so much lead into the atmosphere that it may have lowered citizens’ IQs.