A new voluminous monograph on the history of trade law has hit the shelves. Carlos Petit's Historia del derecho mercantil (Barcelona, Marcial Pons, 2016, 589 p.) presents new insights alongside parts that are based on the author's earlier publications. The scope of the monograph relates to the medieval and early modern period, as well as to the nineteenth century. Even though the book is not explicit on its geographical limits, the focus for the medieval period is on Western Europe and for the sixteenth and subsequent centuries on Spain and its colonies, with references being made to England (ch. 44) and France (ch. 45) as well.
In the introduction and the first chapters, the author demonstrates that the concept of ius mercatorum is fundamentally different from “commercial law” (derecho mercantil). The first relates to a culture of trade, which was based on friendship and courtesy; the latter is concerned with the application of norms and came along with the rise of states. The older mercantile culture according to the author spawned some arrangements and concepts that we still use today. However, transplanting such incrementally developed constructs into the economic culture of the present day results in distortion if the broad fields of meaning from which they stemmed are ignored. The ius mercatorum, which Carlos Petit also labels as lex mercatoria, is defined as belonging to the natural order of late-medieval society, in which every profession played its part. A thirteenth-century conception of trade was therefore benevolent; merchants and trade were considered necessary for the supply of cities, for example (p. 28-29). In an interesting passage, the author explains that the transition from ius mercatorum to “commercial law” was not merely a matter of juridification. Also, it was neither – as Francesco Galgano has contended – a creation of a newly emerging bourgeois class (p. 39, p. 56). According to Carlos Petit the mercantile culture of old and the new state-orientated commercial law co-existed for a long time, until the former was eclipsed by liberal approaches in the course of the nineteenth and twentieth centuries (p. 56-58).
Carlos Petit convincingly argues that in the Middle Ages merchants took into account the implicit rules of society, as well as religion, and that they were occupied mostly with saving their soul and reputation. The monograph is original because it fills up gaps in traditional explanations of developing commercial concepts and arrangements. Petit's analysis of the creation of state banks and how the doctrinal rules on mutuum and societas were bent to the purpose of commercial banking are illuminating (p. 165-263). The creation of the Real Banco (1782) is described in combination with a thorough analysis of the sphere of royal economic governance from which it depended. Interconnections between annuity contracts, deposit banking and land law are analysed with rigour. The author is at his best when he peels historically developed layers of meaning from concepts that have become widely used, such as “company” (p. 180-183) and “accionista” (shareholder) (p. 231-233). The book demonstrates that many rules regarding bills of exchange were referring to the late-medieval mercantile culture (p. 265-314). The intersections between the jurisdiction of mercantile tribunals and the procedural rules of the Roman-canonical procedure are highlighted as well (p. 125-132).
This book is a very welcome and rich addition to the historiography of commercial law. However, also, some arguments might have been expanded a bit more. For example, the reader wonders to what extent references to customs in nineteenth-century codifications could at the same time be products of history, as referring to the older culture of merchants (p. 392), and objectivized, state-bound rules that were to be imposed on mercantile relations (p. 58, p. 313). Were the customs to which merchants abided in the Middle Ages usages (in the sense given to the concept by François Gény, i.e. as based on the will of parties to an agreement) or coutumes (i.e. objective rules, to be applied in the absence of voluntary arrangements)? If mercantile norms were values and usages rather than customs (as suggested on p. 56, and near the end of p. 58), how could they serve to settle disputes? If they were relating more to equity than to objective law, how could mercantile culture, as being effective in a normative sense, be a pan-European, even global, phenomenon of the later Middle Ages? The reader is inclined to draw the conclusion that norms of commerce were constantly being derived from mercantile culture, in courts of merchant-judges, but this poses the question how these processes of translation could result in comparable outcomes in each mercantile court. Such a view is challenged by recent research, a.o. by Emily Kadens, which has pointed to the local scope of and divergence among most late-medieval and early modern customs of trade.
Another theme that invites for further analysis relates to the interactions between doctrine and commercial custom. Merchants were advised to study jurisprudence (p. 68-69, p. 83) and the use of writing by merchants involved the application of learned concepts (p. 83-84). Rules regarding the fraternity among associates and swift procedures can be found both in mercantile tracts and legal treatises (p. 38-41, p. 175). The author explains this as a partial trickling-in of mercantile usages that were described by jurists forasmuch as they related to the themes of their academic writings (p. 39). Yet, also, as was done by Francesco Calasso and Paolo Grossi, the ius commune is defined as being closely intertwined with the “facts of life”. And merchants were complying with prescripts of doctrinal texts and canon law regarding usury (p. 100). If the late-medieval ius commune integrated societal phenomena into the corpus of legal texts, why and to what extent was mercantile law then feasible as standing apart from the ius commune?
But such questions are only incited by the richness of the analysis in the book. Carlos Petit has masterfully combined legal analysis with contextualization. Because of this monograph, the embeddedness of late-medieval and early modern mercantile law within mercantile culture is now an acquis. This book is definitely the chef's special. Legal historians know Carlos Petit's sound writings on many themes, but commercial law is his favorite topic. Any reader will enjoy the author's fluent pen, who demonstrates his broad knowledge and culture (see for example the references to operas in ch. 42 and ch. 47, as revealing contemporary approaches towards mercantile contracts). This work of reference deserves a special place on the bookshelves of legal historians studying pre-modern and nineteenth-century commercial law.
 E. Kadens, The Myth of the Customary Law Merchant, Texas Law Review, 90 (2012), p. 1153-1206.