A key ingredient of these kits was lavender. Historians believe the plant came to Britain as a result of the legions' tradition of cultivating herb gardens where they settled. Lavender belongs to the mint family labiatae and the soldiers grew several members of this large group of aromatic herbs, including rosemary, sage and thyme.
The Romans were aware of the antiseptic and insect-repelling properties of the evergreen shrub with purple flowers. Dioscorides, a Roman physician, had sung its praises back in 100AD. They used it to scent their baths, and its name comes from the Latin lavere, meaning to wash.
The lavender fragrance, which would have reminded tired legionnaires of their Mediterranean homelands, comes from oil glands imbedded among the tiny star-shaped hairs that cover the flowers, leaves and stems. The colourless or yellow oil, now used mainly in perfumes, cosmetics and aromatherapy, is obtained by distilling the flowers. The plants are steamed to vaporise the oils which then liquefy when the steam condenses. About 250kg of lavnder is needed to get just half a litre of oil.
After the Romans had come, seen and departed, the next great cultivators of lavender in Britain were the medieval monks who grew it in their "physick" gardens. By Tudor times, the plant had come to be regarded as a source of "cleanliness and calm". Mixed with charcoal, it was used as a toothpaste. Its flowers were hung in bags around the house to act as natural odour eaters. They were put in drawers to ward off cloth-eating moths and in beds to repel mice and rats.
Perdita gives it a name check in The Winter's Tale when she presents Polixenes and Camillo with "the flower of middle summer", a scene that inspired the Victorian artist Walter Crane (see illustration). The herb was also a hit in the kitchen. Elizabeth I was said to like lavender jam, and the Stuart monarchy had a taste for lavender wine. But it was still in most demand for its medicinal qualities. The plant was burned in the streets to try to clean the air during the plague years before the Great Fire.
These qualities came to the fore again during the First World War when Europe began to run out of disinfectant. Women in Britain gathered lavender so that the oil could be poured on moss to dress the soldiers' wounds. From Caesar to Kaiser Bill, how little had changed.