Caesar’s favourite herb was the Viagra of ancient Rome. Until climate change killed it off

Perfume, tonic - even love potion - silphium was prized by the ancient Romans, but in its success lay the seeds of its own downfall

Of all the mysteries of ancient Rome, silphium is among the most intriguing. Romans loved the herb as much as we love chocolate. They used silphium as perfume, as medicine, as an aphrodisiac and turned it into a condiment, called laser, that they poured on to almost every dish. It was so valuable that Julius Caesar stashed more than half a tonne in his treasury.

Yet it became extinct less than a century later, by the time of Nero, and for nearly 2,000 years people have puzzled over the cause.