Weatherwatch: Wrapping up warm on Hadrian's Wall

The climate in England during the Roman occupation was roughly as now; warm enough to have vineyards, some as far north as Yorkshire. But while the Romans, like us, had central heating, they spent a lot more time outdoors. It was colder in a chariot, on a horse, or marching than in a modern car. Sentry duty on Hadrian's Wall must have been tough even for locally recruited soldiers.

A fragment of a letter written there 1,900 years ago on 4 October by an officer, Flavius Cerialis, to a friend said that he has found the answer, a British overcoat made of wool. This garment known as the birrus Britannicus later became a fashion item among Romans and was exported in large numbers. Two hundred years later the Emporer Diocletian detailing the finest goods and services traded across the Empire includes this garment, the only British export to make the list.

On mosaics and a sculpture from Housestead's Fort on Hadrian's Wall the birrus Britannicus is shown as a long cloak with a hood. It seems to have been in the colour of the original sheep, made with untreated wool and so kept the rain out. Such a cloak would also make a make a useful waterproof blanket if sleeping out.

Roman prices are hard to compare but the finest birrus Britannicus for export were quoted as 6,000 denarii, three months wages for a teacher, or enough to buy 300 kilos of pork or 500 litres of cheap wine.

• Roman Britain
• Weatherwatch
• features

ncG1vNJzZmivp6x7tbTEoKyaqpSerq96wqikaKaVrMBwfo9qamink6l8cYKOsJyarJiav7it05yfZqCRmb%2Bqrc2sZLCZnKF6s7vMmqVmq5%2Bhsaqx0WauqKecYrCtu8Ck