The Common Law (and not Roman) Origins of Amicus Curiae in International Law

The possibility for private entities interested in international trials but without the legal requirements to participate as a party was precluded, in a classical vision of international law made for states and addressed to states. At present, however, with some notable exceptions, several international jurisdictions allow for the submission of amicus curiae briefs. These briefs were introduced to international courts by common law lawyers. Legal literature generally identifies it as an institution of classical Roman law. This paper will show that this assumption is, however, doubtful. An examination of the sources cited by an important dictionary and other decades-old legal scholarship relied upon today as establishing the Roman origins of amicus curiae, and a fresh study of Roman and later continental European primary sources reveal a different picture: In reality, there is neither a basis for grounding the amicus curiae in Roman law, nor is there a basis for grounding it in the medieval continental ius commune. The primary source is most likely English common law and, not surprisingly, it was common law lawyers who introduced the briefs into international litigation.