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Fragment of a
perpetual calendar

Copper alloy

Vindolanda, Roman
fort and settlement,
northern England

Mixed with the
rubble and
collapsed wall
of a granary

3rd-4th century A.D.

About 3 inches long

a line of punched
holes each representing
two days; and "K" for Kalends,
or the first day of the month;
"N" for the Nones, or fifth day;
"I" for the Ides, or 13th day;
and "AE," an abbreviation for
Aequinoctium, the autumn
Equinox on
September 23


(Courtesy Andrew Birley, The Vindolanda Trust)

Last summer, archaeologists excavating for the 38th season at the Roman fort settlement of Vindolanda along Hadrian's Wall in northern England discovered this piece of an ancient perpetual calendar, an annual type not tied to any particular year. It's one of only three ancient portable calendars ever found, joining a Celtic one engraved on a bronze tablet unearthed in Coligny, France, in 1897, and a Roman bronze menologium (register of months) from a well at the site of le Cagnot at Grand, France, in 1886. The calendar is the first object of its type to come from Roman Britain and the only one from a scientific excavation.

The Roman army's success depended on its regimented lifestyle, which included the observance of festival days and harvest times. While in larger towns and cities a calendar would have been inscribed or painted on the side of a building, a portable calendar like this allowed the army to keep track of the date at all times, even while on the march, ensuring strict adherence to this prescribed yearly cycle. If complete, the calendar would have been a circular disk about 12 inches in diameter. Every two days a peg (not found) would have been moved into the next hole, indicating the correct date.

Vindolanda has yielded more evidence about daily life on the Roman frontier than almost any other site. Soldiers, slaves, merchants, women, and children are all represented in more than 1,400 writing tablets that have been recovered there. These documents include the earliest examples of female handwriting from western Europe, demands for beer, requests for leave, and references to the "nasty little Brits" in the region surrounding the Roman fort. The calendar now also gives us insights into how they marked the passage of time.

Andrew Birley is Director of Excavations at the Vindolanda Trust.