The siliqua is the modern name given to small, thin, Roman silver coins produced from 4th century and later.
The term siliqua comes from the siliqua graeca, the seed of the carob tree, which in the Roman weight system is equivalent to 1/6 of a scruple (1/1728 of a Roman pound or about 0. The Carob tree (from Arabic: خروب "kharūb" and Hebrew: חרוב Charuv) Ceratonia siliqua, is a Leguminous The ancient Roman units of measurement were built on the Hellenic system with Egyptian, Hebrew, and Mesopotamian influences The ancient Roman units of measurement were built on the Hellenic system with Egyptian, Hebrew, and Mesopotamian influences 19 gram). For other uses of the words gram or gramme see Gram (disambiguation.
Siliqua vicesima quarta pars solidi est, ab arbore, cuius semen est, vocabulum tenens.—Isidore of Seville, Isidore of Seville
The term has been applied to the various silver coins on the premise that the coins represented that were valued at 1/24 of the gold solidus (which weighed 1/72nd of a Roman pound) and therefore represented a siliqua of gold in value. The solidus (the Latin word for solid) was originally a Gold coin issued by the Romans. Since gold was worth about 14 times as much as silver in ancient Rome, such a silver coin would have a theoretical weight of 2. In the Physical sciences weight is a Measurement of the gravitational Force acting on an object 7 grams.
There is little historical evidence to support this. This has not prevented the term from being applied to silver coins issued by Constantine, which initially weighed 3. Flavius Valerius Aurelius Constantinus (27 February ca. 272 &ndash 22 May 337 commonly known as Constantine I, Constantine the Great, or Saint Constantine 4 grams, or the later silver coin of Constantius II, which weighed about 2. Flavius Iulius Constantius, known in English as Constantius II ( 7 August, 317 - November 3, 361) was a Roman Emperor 2 grams and 18mm, and is sometimes called a "light" or "reduced" siliqua to differentiate it.
The term is one of convenience as no name for these coins is indicated by contemporary sources. Thin silver coins to the 7th century which weigh about 2 to 3 grams are known as siliqua by numismatic convention.