Dante Fedele’s new work of reference reveals the medieval foundations of international law through a comprehensive study of a key figure of late medieval legal scholarship: Baldus de Ubaldis (1327-1400). A student of Bartolus de Sassoferrato, Baldus wrote both extensive commentaries on Roman, canon and feudal law and thousands of consilia originating from particular cases. His writings dealt with numerous issues related to sovereignty, territorial jurisdiction, diplomacy and war, combining a rich conspectus of earlier scholarship with highly creative ideas that exercised a profound influence on later juristic thought. The detailed picture of the international law doctrines elaborated by a prominent medieval jurist offered in this study contributes to our understanding of the intellectual archaeology of international law. "Dr. Fedele’s monograph will no doubt become a necessary work of reference for any scholar interested in the history of international law. [...] Beyond the specific doctrines on particular areas of international law, Dr. Fedele’s study of Baldus shows how in the area of international governance, jurists sought to marshal different expressions of normativity." - Alain Wijffels, Foreword