Coinage and Money in the Roman Jurists’ Thought

Roman jurists’ thinking on currency finds many points of contact with Aristotle’s treatment of money. Proculians and Sabinians share the idea that money was established to fulfill the function of measurement (publica ac perpetua aestimatio): its original function, for both schools of thought, is that of value measure. For the Sabinians this function is sufficient to bring the exchange of thing (res) against thing within the scheme of selling for money (emptio-venditio). Conversely, for the Proculians, the institution of coined money as a medium of exchange (…materia forma publica percussa…) makes this assimilation impossible. This was not for economic or social reasons but because of the cogent force of mechanisms in the world of law: the obligations of seller (venditor) and buyer (emptor) are not the same and, therefore, legal actions to compel an exchange (actiones venditi and empti) are unsuitable when the object of exchange did not coincide with either the commodity to be transferred (merx) or the price (pretium) fixed in money (pecunia numerata). Money represents the unit of measure, but this does not mean that its power, as a medium of exchange (or payment), is always the same. Jurists knew, as did Aristotle, that money was not, as such, a store of value protected from any possibility of variation.