Silphium was a herb that existed in the ancient world, and was apparently used so much that the plant was driven into extinction, as there is no currently existing plant that matches its description. Silphium’s main use was as a contraceptive, and secondarily as an abortifacent.
The herb’s first appearance in the historical record is in the 7th century BCE in Egypt. We know that the plant was particularly heavily cultivated in the Greek city of Cyrene, in modern-day Libya, with silphium being so central to the colony’s economy that it appeared on all their coins. It seems, however, that the plant was already extinct by the 1st century BCE.
Some believe that our modern “heart” symbol (❤️) is taken from the shape of a silphium seed.