Ancient Roman units of measurement

Greaves visited Rome in 1639, and measured, among other things, the foot measure on the tomb of Titus Statilius Aper, that on the statue of Cossutius formerly in the gardens of Angelo Colocci, the congius of Vespasian previously measured by Villalpandus, a number of brass measuring-rods found in the ruins of Rome, the paving-stones of the Pantheon and many other ancient Roman buildings, and the distance between the milestones on the Appian Way.

[4][5] The Roman foot was sub-divided either like the Greek pous into 16 digiti or fingers; or into 12 unciae or inches.

[6] The principal Roman units of length were: Other units include the schoenus (from the Greek for "rush rope") used for the distances in Isidore of Charax's Parthian Stations (where it had a value around 5 km or 3 miles)[8][9] and in the name of the Nubian land of Triacontaschoenus between the First and Second Cataracts on the Nile (where it had a value closer to 10.5 km or 6+1⁄2 miles).

[10][11] The ordinary units of measurement of area were: Other units of area described by Columella in his De Re Rustica include the porca of 180 × 30 Roman feet (about 473 m2 or 5,090 sq ft) used in Hispania Baetica and the Gallic candetum or cadetum of 100 feet[clarification needed] in the city or 150 in the country.

Columella also gives uncial divisions of the jugerum, tabulated by the anonymous translator of the 1745 Millar edition as follows: Both liquid and dry volume measurements were based on the sextarius.

Using the value 296 mm (11.7 in) for the Roman foot, an amphora quadrantal can be computed at approximately 25.9 L (5.7 imp gal; 6.8 US gal), so a sextarius (by the same method) would theoretically measure 540.3 ml (19.02 imp fl oz; 18.27 US fl oz), which is about 95% of an imperial pint (568 ml).

In 321, Constantine the Great gave his subjects every Sunday off in honor of his family's tutelary deity, the Unconquered Sun, thus cementing the seven-day week into Roman civil society.

The Romans divided the daytime into twelve horae or hours starting at sunrise and ending at sunset.