For nearly 2,000 years the most prized medicine in the world was theriac, a dark red paste of 64 ingredients including dried scorpion, Dead Sea bitumen and roasted viper flesh, still sold in some Italian pharmacies into the 1930s and the origin of the English word treacle. It began with Mithridates VI of Pontus, who feared poison so much that he reportedly tested poisons and remedies on prisoners and blended the winners into mithridatium, about 40 ingredients strong. After Pompey conquered him, the recipe reached Andromachus, physician to Nero, who expanded it to 64 and added viper flesh on the logic that a venomous beast must hold its own antidote.

In the Middle Ages theriac took on spiritual meaning. Henry of Grosmont, Duke of Lancaster, likened it to purging sin, and during the Black Death, blamed on sin and mythical serpents, physician Gentile da Foligno, who died of plague in 1348, urged it be aged a year. Venice built a monopoly on Venice treacle and staged public preparations in town squares until French apothecary Moyse Charas published the recipe in 1669. Modern analysis points to the real reason patients felt relief: large amounts of opium.

• How Western envoys presented theriac to Tang Emperor Gaozong in 667 AD as a cure for a hundred ailments
• London’s Worshipful Company of Grocers policing counterfeits of imported theriac
• Galen’s claim that it peaked at six years of aging and stayed potent for 40
• The 150 kilogram batch prepared in Maastricht in 1712
• A 1683 Amsterdam recipe with castoreum from beavers, copper salts, honey and wine