Keywords: Koskenniemi; International Law; History of Ideas; Legal Concepts.
International law, though somehow confuted by recent (and sad) developments in international relations and world affairs, is more than ever flourishing as an academic field of research. In particular we begin to have solid and intelligent studies in the history of international law, both as a province of ideas and as an institutional camp for political fight. Within the increasing historical production in this area, Marti Koskenniemi's work is of an outstanding quality. His books and articles reveal a great technical competence and a vocation for philosophical interrogation. But the best he probably gives is in the history of ideas. This paper deals with Koskenniemi's approach as a historian of political and legal theory and with his methodological approach and more or less explicit normative claims. His perspective is then compared with the two most influential schools in the history of ideas, Quentin Skinner's linguistic contextualism and Reinhart Koselleck's Heideggerian "Historie". A critical assessment will be the outcome of such exercise.