We all know the incredible stories surrounding so many of the late Roman Emperors.
We also know that the Roman Empire FELL.
Here is one very plausible theory I heard about this week: Lead Poisoning. Rome mined huge quantities of lead and it was a part of daily life. In fact, so much lead mining and smelting took place in the Mediterranean that lead traces have been found in ice core samples taken in Greenland. (Stay with me, people.)
A number of Roman scholars, and even the Greek physicians before them, were aware of the possible links between lead and ill health, but perhaps the link was too tenuous for them to take more seriously.
Water was brought into town via lead pipes, and lead was used to line the aqueducts. So ingrained in modern culture is it that our word plumbing comes from plumbum, the Latin word for lead which is immortalised as Pb on the periodic table. (Just look at how many Victorian lead pipes we have had to replace in recent decades.)
Roman women, in order to preserve their light complexions, powdered their faces with white lead. Prolonged use most likely caused skin damage, thereby necessitating further use.
Roman food was cooked in lead pots or lead-lined copper pots. I'm pretty sure that earthenware glaze contained lead back then too. (A bit ironic (sorry) that lead wasn't added to glass until the 17th century. This is the reason that so much Roman glass is cloudy and iridescent.)
The Roman upper classes drank large quantities of neat and diluted wine; much of it was flavoured with various forms of unfermented grape syrups, also used as flavour enhancers in cooking. First there was Mustum. Mustum could be reduced by half into Defrutum, and further into a third as a syrup called Sapa. All, of course, boiled down in lead pots and because of the grapes' acidity, even more toxin would leach into the mix.
The presence of lead in the wine not only served to sweeten it, improve the colour and add bouquet, but acted as a preservative for export to all corners of the Empire. (On a side note, the Greeks, who had once been the world's producer, added pine resin.)
And so to the mad Emperors and the decline of the Empire: Lead is a neurotoxin. It also causes infertility.
Looking at the afflictions of Claudius, many doctors see this as a classic case of lead poisoning: excruciating stomach pains, speech impairment, weak limbs, slobbering or drooling, fits of laughter. To complete the vicious cycle, he was an alcoholic.
Then there are the wild orgies, drunken Bacchanals, erratic and scandalous behaviour, and illogical decisions of Commodus, Nero, Caligula, Tiberius, and the weirdest one, Elagabalus.
He was so crazy, even the lead-poisoned citizens wanted to get rid of him.
The birth rate eventually dipped so low, that couples were penalised if they had too few children.
So if the rulers and decision-making upper classes were poisoned, how long before the moral decay and population decline leach into the civil and economic health of an Empire?