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The measures of the legions, from the digitus to the mile. Part of the Ancient Measures collection.
Every unit converts through meters. The standard values: pes = 0.296 m, digitus = pes/16, uncia = pes/12, cubitus = 1.5 pedes, passus = 5 pedes, mille passus = 1000 passus. Worked example: a Roman mile = 1000 × 1.48 = 1480 m — about 8% shorter than the modern statute mile of 1609 m. The pes varied slightly by province and century (29.4–29.7 cm); 29.6 cm is the scholarly consensus.
29.6 cm — about 3% shorter than the modern foot of 30.48 cm. Surviving bronze and bone rulers cluster tightly around this value across the empire.
Almost: our word comes from mille passus, a thousand double-steps (1.48 km). Elizabeth I's statute mile (1609 m) is longer — the Romans would have called it about 1088 passus.
A double step — the distance covered in two strides, 5 pedes (1.48 m). Legionaries drilled to march 20,000 passus in five hours; milestones counted them.
Roman Weight Roman Volume Greek Length Jewish Length Russian Length