What this unit was
Roman cyathus is modelled here as a liquid standard of the Roman tradition, associated with Roman world during Late Republic to Imperial representative. The converter represents one cyath. as 0.0455 L; its basis is one-twelfth-sextarius. The matrix carries an indicative uncertainty of ± 0.00083333333 L.
Within that setting, the unit belonged to a working system for storage, rations, trade, and the circulation of drink or other commodities. It should be read with its period, locality, and evidential basis attached, not as a universal value shared by every culture using a similar name. A vessel name is not automatically the capacity of every surviving vessel.
Evidence of use and sources
The working value is traceable to Smith Dictionary Mensura. Its record is classified as high confidence and uses the stated basis rather than an assumed culture-wide constant.
Three directly pertinent excerpts from the supplied library are available.
“The rest of the Measures are founded on known proportions.”
Tables of antient coins, weights, and measures, PDF p. 78. reconstructed proportional systems
“Stadium contain'd 125 Roman Paces, or 625 Feet”
Tables of antient coins, weights, and measures, PDF p. 81. Roman distance relationship
“the trade value of the Attic standard, and ... the coinage value”
Flinders Petrie, Ancient Weights and Measures, PDF p. 31. trade and coin systems must be distinguished
Working definition
Roman cyathus is represented as a Roman standard associated with Roman world during Late Republic to Imperial representative.
The converter uses 0.0455 L per unit with indicative matrix uncertainty ± 0.0008333333333 L.
How to use it
Basis: one-twelfth-sextarius; confidence: high. A shared historical name does not make this value portable to another period or polity.
Open this unit in the Liquid converter · Return to all units