Cyrene was established by the Greecs in 531 BC, and the place was chosen because of its fertile land and rich in water supplies.

Silphium is a plant that was heavily growing in the now known Qourina (Cyrene) in the Green mountain area in Eastern Libya.

Exports of the plant and its resins made Cyrene the richest city on the continent at that time. It was so valuable, in fact, that Cyrenians began printing it on their money. Silver coins from the 6th century B.C. are imprinted with images of the plant’s stalk—a thick column with flowers on top and leaves sticking out—and its seed pods, which look pretty familiar with its heart shape appearance.

So what was so great about silphium sap?. It was at that time, a kind of cure-all, used to treat everything from chills to fevers to corns. Hippocrates said: it could be used as a poultice, or to soothe the stomach. Cooks also used the plant in their recipes, perhaps the same way we use fennel seeds today.

It may also have been used as a type of birth control. “Anecdotal and medical evidence from classical antiquity tells us that the drug of choice for contraception was silphium,” writes the historian John Riddle in Eve’s Herbs: A History of Contraception and Abortion in the West. He points to the ancient physician Soranus, who suggested taking a dose of silphium “the size of a chick-pea” once a month, both to prevent conception and “destroy any already existing.”

Silphium seeds looked heart shaped by their understanding at those days, as the heart at that time was not seen or imagined as we know it in our current knowledge. The heart was thought to be formed of three chambers, and that was probably the reason why silphium seeds where linked to the heart shape, then obviously became historically as the first sign of love.

In his Poem, Catullus wrote that he wants to share as many kisses with his beloved “as the number of Libyan sands that lie in silphium-bearing Cyrene.” It’s not too hard to imagine that he’s providing two prescriptions at once here: one for getting busy and one for preventing unintended consequences. Riddle also describes another, more explicit Cyrenian coin: “A seated woman has silphium at her feet, while one hand touches the plant and the other points to her reproductive area.”

Not everyone buys Riddle’s theory about silphium’s ancient use. In a 1994 New York Times article, other experts called it an “intriguing hypothesis” but went no further, saying there’s not quite enough evidence to crown the plant as a common form of ancient birth control. And even if we grant it that status, it’s still a bit of a leap from “heart-shaped seed of ancient contraceptive plant” to “enduring symbol of love.” There are also plenty of other theories about where the heart shape came from, ranging from a Catholic saint’s divine hallucinations to a bad organ description by Aristotle.