Introduction

The role of Roman law in the development of international law has been appreciated in quite different ways. In some manuals, such as those by Nussbaum, Grewe and Truyol y Serra, this role has certainly been underestimated. Another position is defended by Ziegler: from his earlier publications until his recent general survey on the history of international law, he has shown a wide variety of influences of Roman law on the development of international law. Of course, this difference in appreciation of the role of Roman law is closely linked with what I would like to call the ‘minimalist’ and ‘maximalist’ approaches to the history of international law. A ‘minimalist’ concept defines international law as law between sovereign states. Sovereignty in the modern sense does not appear before the sixteenth century, so, therefore, the ‘real’ history of international law does not start until the early modern period. In the minimalist opinion, there has hardly ever been any interest in the question whether the concepts of international law have been influenced by Roman law.

On the other hand, the ‘maximalist’ approach applies a wider concept of ‘international’, so that the earliest forms of peace treaties mark the beginning of the history of international law. The great problem for the ‘maximalist’ approach concerns the Middle Ages, when the emperor of the medieval Holy Roman Empire of the Germanic Nation and the pope both claimed universal recognition, which seems to exclude the existence of international law.