The state of peace becomes a necessity when exchange becomes a regular phenomenon. In cases where there were insufficient preconditions for keeping the peace, the persons engaged in exchange preferred to each inspect the commodities separately, in the absence of the other party, rather than meeting together personally. In general, however, trade requires that not only the commodities, but the people too come together. In the epoch of the gens-system, every stranger was regarded as an enemy: he was free game, just like the beasts of the forests. Only the custom of hospitality provided an opportunity for intercourse with alien tribes. In feudal Europe, the Church attempted to check the incessant private wars by proclaiming the so-called treuga dei at certain intervals. Simultaneously, markets and trading centres began to be endowed with appropriate special concessions. Merchants going to market received safe conduct, their property was protected against arbitrary seizure. At the same time, the fulfilment of contracts was guaranteed by special judges. In this way, a special jus mercatorium or jus fori arose, which formed the basis of later municipal law.
Originally, market places and fairs were part and parcel of feudal demesnes, and were simply advantageous sources of income for the local feudal lord. Whenever a place was granted market peace, the sole purpose of the this was to fill the purse of the some feudal lord, so that it was in his private interest. Yet thanks to its new role as guarantor of the peace indispensable to the exchange transaction, feudal authority took on a hue whach had hitherto been alien to it: it went public. The feudal or patriarchal mode of authority does not distinguish between the private and the public. The feudal lord’s public rights with regard to the serfs were simultaneously his rights as a private owner, whereas his private rights, on the contrary, may be interpreted, if one so wishes, as political, and therefore public rights. This is exactly the way in which many people (including Gumplowicz) interpret the jus civile of ancient Rome as a public law, since it was founded on, and originated here with an embryonic form of law, which has not yet developed within it the contradictory, yet correlate, determinants ‘private law’ and ‘public law’. That is why any form of power which bears traces of patriarchal or feudal relations is also characterised by the predominance of theological rather than legal aspects. Only the development of trade, and of the money economy, make the juridical, or rationalistic, interpretation of the phenomenon of power possible. It is these economic forms which first introduce the contradiction between public and private life, a contradiction which assumes, over time, an ‘eternal’ and ‘natural’ character, and forms the basis of every juridical theory of power.
The ‘modern’ state (in the bourgeois sense) comes into being at that point in time when the organisation of power by groups or classes encompasses a sufficiently expanded acrivity in market transactions. Thus in Rome, trade with foreigners, resident alens (peregrini) and others, demanded acknowledgment of legal capacity in the civil sphere in people who were not members of the gens-association. This already presupposes, however, a distinction between public and private law.
Evgeny B. Pashukanis, Law & Marxism, trans. Barbara Einhorn (London, Pluto Press 1978) p.135–6