by David Fox, Professor of Common Law, University of Edinburgh
Introduction
The opening text of Book XVIII of Justinian’s Digest, on the contract of purchase, quotes an excerpt from Paulus’ Commentary on the Edict.[1] In this text, Paulus develops a legal test for distinguishing two kinds of exchange: the contract of purchase (emptio) on the one hand and the contract of barter (permutatio) on the other. Purchase, he says, consists in one party paying a money price (pretium) in exchange for the thing (merx) that is promised and delivered by the other party. By contrast, a barter is a transaction where the parties promise and exchange two non-monetary things.
Paulus goes on to develop a sharp definition of money for the purposes of his rule. The monetary price, he says, should consist in coins (nummi) struck in authorised form by the public mint. For Paulus, the delivery of coined money on one side of the exchange marks the identifying characteristic of a contract of purchase.
Justinian authoritatively accepted Paulus’ view.[2] His ruling put beyond dispute that purchase and barter were distinct contracts in the revived Roman law of the sixth century AD, and that each had to be enforced by its own distinct actions. In so ruling, he settled an old disagreement between the Sabinian and Proculian schools of juristic thought.[3]
Leave a Comment