The Medieval Foundations of International Law

Baldus de Ubaldis (1327–1400), Doctrine and Practice of the Ius Gentium


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

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Dante Fedele, Ph.D. (2014), is Research Fellow at the CNRS (CHJ UMR 8025 - Lille). His publications on the history of diplomacy and international law include Naissance de la diplomatie moderne (XIIIe-XVIIe siècles). L’ambassadeur au croisement du droit, de l’éthique et de la politique (Nomos, 2017).

1 Introduction
 1 ‘International Law’ in the Middle Ages
 2 The ‘Medieval Foundations’ of International Law
 3 Baldus de Ubaldis
 4 Structure
 5 A Note on the Sources

2 Universal Authorities and Territorial Polities
 1 The Emperor’s Sovereignty
  1.1 The Emperor ‘Lord of the World’
  1.2 The Universality of Imperial Sovereignty
  1.3 Summary
 2 The Pope’s Sovereignty and the Relationship between the Emperor and the Pope
  2.1 The Pope’s Sovereignty
  2.2 The Relationship between the Emperor and the Pope
   2.2.1 Imperial Coronation
   2.2.2 The Pope’s Exercise of the Imperial Vicariate During a Vacancy in the Empire
   2.2.3 The Papal Right to Depose the Emperor
  2.3 The Pope’s Sovereignty in the Lands of St Peter
  2.4 Summary
 3 Kingdoms
  3.1 ‘Rex Superiorem Non Recognoscens in Regno Suo Est Imperator’
  3.2 The Relationship between Kingdoms and the Empire
  3.3 The Relationship between Kingdoms and the Church
  3.4 Summary
 4 Signorie and Vicariates
  4.1 The Legitimation of Seigneurial Rule
  4.2 Giangaleazzo Visconti and His Ducal Titles
  4.3 Summary
 5 Cities That Recognise No Superior
  5.1 The Juristic Debate on Cities’ Autonomy
  5.2 The Foundations of Cities’ Autonomy
  5.3 Cities belonging to the Papal Lands
  5.4 Summary

3 Feudo-Vassalic Relations and Territorial Jurisdiction
 1 Feudo-Vassalic Relations
  1.1 ‘Feudum a Fidelitate’
  1.2 The Vassal’s Obligation to Respond to the Lord’s Call to Arms
  1.3 The Prohibition against the Alienation of Fiefs, and the Resolution of Feudal Disputes
  1.4 The Public Character of Feuda Dignitatum
  1.5 Summary
 2 Territory and Jurisdiction (i)
  2.1 ‘Territorium a Terrendo’
  2.2  ‘Iurisdictio Cohaeret Territorio’
  2.3 The Grant of a Castrum
  2.4 The Prescription of Jurisdiction
 3 Territory and Jurisdiction (ii)
  3.1 The Boundaries of Territory
  3.2 The Sea
  3.3 Summary
  4 Conflicts of Laws and Jurisdiction
 4.1 Citizenship and Foreignness
  4.1.1 Native and Naturalised Citizens
 4.1.2 Foreigners
 4.2 The Conflict of Laws
 4.3 Conflicts of Laws and Jurisdiction in Criminal Matters
 4.3.1 The Forum Loci Delicti
 4.3.2 The Forum of the Defendant’s Place of Origin
 4.3.3 The Forum of the Defendant’s Place of Residence, and the Prosecution of Foreigners for Offences Committed Abroad
 4.3.4 Summons and Extraditions
 4.3.5 Bis in Idem
 4.4 Summary

 1 The Office of Ambassador
 1.1 The Ambassador and the Papal Legate
 1.2 The Actors Entitled to Send Ambassadors
 1.3 The Ambassador’s Appointment and the Compulsory Nature of the Office
 1.4 The Right to a Salary or Reimbursement for Losses
 1.5 The Capacity to Accept or Solicit Gifts
 1.6 Inviolability, Immunities and Other Privileges
 1.7 Summary
 2 The Ambassador’s Negotiating Powers and the Ratification of Treaties
 2.1  Nuntius, Procurator and Syndicus
 2.2 Procurations
 2.3 The Ratification of Treaties
 2.4 The Effects of Treaties on Individual Citizens
 2.5 Summary
 3 The Observance of Treaties
 3.1 The Binding Force of Agreements
 3.1.1 Agreements Concluded by the Emperor or the Pope
 3.1.2 Agreements Concluded by Kings
 3.1.3 Agreements Concluded by Cities
 3.2 Exceptions to the Principle
 3.2.1 Vices of Consent,Causa, and the Public Utility
 3.2.2 The Implied Clauses Rebus sic se Habentibusand Frangenti Fidem Fides Frangitur
 3.3 Summary
 4 Leagues, Adhaerentiae and Submissions
 4.1 Leagues
 4.1.1 The Legitimacy of Leagues
 4.1.2 Leagues as Corporate Bodies
 4.1.3 League Treaties as ‘Contracts of Strict Law’
 4.1.4 The Rights and Obligations of Allies
 4.2 Adhaerentiae
 4.3 Submissions
 4.4 Summary

5War and Reprisals
 1 The Conditions of Just War
 1.1 Late Medieval Categorizations of Just War Conditions
 1.2 Legitimate Authority
 1.3 Just Cause
 1.3.1 War of Aggression
 1.3.2 Defensive War
 1.3.3 War of Recovery
 1.3.4 Unilateral or Bilateral Justice
 1.4 Summary
 2 The Conduct of War
 2.1 The Scope of Diffidatio and the Obligation to Serve in the Army
 2.2 The Soldiers’ Responsibility, Obligations and Rights
 2.3 The Limitation of Violence in War (Moderamen, Pax Dei and Treuga Dei)
 2.4 Truces between War and Peace
 2.5 Summary
 3 The Law of Booty and Captives
 3.1 General Principles
 3.2 The Law of Booty
 3.3 The Occupation of Foreign Territory
 3.4 The Law of Captives
 3.4.1 The Status of Captives
 3.4.2 Captives and Captors
 3.4.3 Postliminium and the Redemption of Captives
 3.5 Summary
 4 Peacemaking and the Safeguarding of Peace
 4.1 The Meaning of Pax
 4.2 Arbitrations
 4.3 Amnesty and Restitution Clauses
 4.4 The Status of Conquered Territories
 4.5 The Safeguarding of Peace
 4.6 Summary
 5 Reprisals
 5.1 Reprisals between Practice and Doctrine
 5.2 The Legitimacy of Reprisals
 5.3 Reprisals and Citizenship
 5.4 The Granting and the Execution of Reprisals
 5.5 Summary




Scholars and students of legal history and history of international law, and anyone interested in late medieval Italy and history of political thought.
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