Course: International Relations
Unit: Foundations of International Relations
Stephen Waweru
Topic Two: History and Evolution of the International System
1. INTRODUCTION
The international system did not emerge overnight. It has undergone transformations shaped by
war, diplomacy, empire, ideology, and legal norms. This session examines the historical
milestones that laid the foundation of the current international order.
2. THE TREATY OF WESTPHALIA (1648): THE BIRTH
OF THE MODERN INTERNATIONAL SYSTEM
Background
The Treaty of Westphalia concluded the Thirty Years’ War and marked a turning point in
European and global diplomatic history. It ushered in the legal principles of territorial
sovereignty and state autonomy.
Page 1 of 35
,The Peace of Westphalia and Sovereignty
Learning Objective
Explain the significance of the Peace of Westphalia on European politics and diplomacy.
Key Points
The Peace of Westphalia was a series of peace treaties signed between May and October
1648 in the Westphalian cities of Osnabrück and Münster. The treaties ended the Thirty
Years’ War and the Eighty Years’ War.
The Thirty Years’ War was a series of wars in Central Europe between 1618 and 1648.
Initially a war between various Protestant and Catholic states in the fragmented Holy
Roman Empire, it developed into a conflict involving most of the great powers.
The Eighty Years’ War, or Dutch War of Independence (1568–1648), was a revolt of the
Seventeen Provinces against the political and religious hegemony of Philip II of Spain,
the sovereign of the Habsburg Netherlands.
According to the Peace of Westphalia, all parties would recognize the Peace of Augsburg
of 1555; Christians of non-dominant denominations were guaranteed the right to practice
their faith; and the exclusive sovereignty of each party over its lands, people, and agents
abroad was recognized.
Multiple territorial adjustments were also decided.
The Peace of Westphalia established the precedent of peace reached by diplomatic
congress and a new system of political order in Europe based upon the concept of co-
existing sovereign states. The Westphalian principle of the recognition of another state’s
sovereignty and right to decide its own fate rests at the foundations of international law
today.
The European colonization of Asia and Africa in the 19th century and two global wars in
the 20th century dramatically undermined the principles established in Westphalia.
Terms: cuius regio, eius religio
Page 2 of 35
,A Latin phrase that literally means “Whose realm, his religion,” meaning that the religion of the
ruler was to dictate the religion of those ruled. At the Peace of Augsburg of 1555 the rulers of the
German-speaking states and Charles V, the emperor, agreed to accept this principle.
The Eighty Years’ War
A revolt, known also as the Dutch War of Independence (1568–1648), of the Seventeen
Provinces against the political and religious hegemony of Philip II of Spain, the sovereign of the
Habsburg Netherlands.
The Thirty Years’ War
A series of wars in Central Europe between 1618 and 1648. Initially a war between various
Protestant and Catholic states in the fragmented Holy Roman Empire, it gradually developed into
a more general conflict involving most of the great powers.
The Peace of Westphalia
A series of peace treaties signed between May and October 1648 in the Westphalian cities of
Osnabrück and Münster. The treaties ended the Thirty Years’ War (1618–1648) in the Holy
Roman Empire and the Eighty Years’ War (1568–1648) between Spain and the Dutch Republic,
with Spain formally recognizing the independence of the Dutch Republic.
Westphalian sovereignty
The principle of international law that each nation-state has sovereignty over its territory and
domestic affairs, to the exclusion of all external powers, on the principle of non-interference in
another country’s domestic affairs, and that each state (no matter how large or small) is equal in
international law. The doctrine is named after the Peace of Westphalia, signed in 1648.
Peace of Augsburg of 1555
A treaty between Charles V and the forces of the Schmalkaldic League, an alliance of Lutheran
princes, on September 25, 1555, at the imperial city of Augsburg, in present-day Bavaria,
Page 3 of 35
, Germany. It officially ended the religious struggle between the two groups and made the legal
division of Christendom permanent within the Holy Roman Empire.
Introduction
The Peace of Westphalia was a series of peace treaties signed between May and October 1648 in
the Westphalian cities of Osnabrück and Münster. The treaties ended the Thirty Years’ War
(1618–1648) in the Holy Roman Empire and the Eighty Years’ War (1568–1648) between Spain
and the Dutch Republic, with Spain formally recognizing the independence of the Dutch
Republic. The peace negotiations involved a total of 109 delegations representing European
powers. The treaties did not restore peace throughout Europe, but they did create a basis for
national self-determination.
Background: Wars in Europe
Two destructive wars were the major triggers behind signing the eventual Peace of Westphalia:
the Thirty Years’ War in the Holy Roman Empire and the Eighty Years’ War between Spain and
the Dutch Republic.
The Thirty Years’ War was a series of wars in Central Europe between 1618 and 1648. Initially a
war between various Protestant and Catholic states in the fragmented Holy Roman Empire, it
gradually developed into a more general conflict involving most of the great powers. The war
began when the newly elected Holy Roman Emperor, Ferdinand II, tried to impose religious
uniformity on his domains, forcing Roman Catholicism on its peoples. The northern Protestant
states, angered by the violation of their rights to choose granted in the Peace of Augsburg,
banded together to form the Protestant Union. These events caused widespread fears throughout
northern and Central Europe, and triggered the Protestant Bohemians living in the dominion of
Habsburg Austria to revolt against their nominal ruler, Ferdinand II. They ousted the Habsburgs
and instead elected Frederick V, Elector of Palatinate, as their monarch. Frederick took the offer
without the support of the union. The southern states, mainly Roman Catholic, were angered by
this. Led by Bavaria, these states formed the Catholic League to expel Frederick in support of the
emperor.
Page 4 of 35
Unit: Foundations of International Relations
Stephen Waweru
Topic Two: History and Evolution of the International System
1. INTRODUCTION
The international system did not emerge overnight. It has undergone transformations shaped by
war, diplomacy, empire, ideology, and legal norms. This session examines the historical
milestones that laid the foundation of the current international order.
2. THE TREATY OF WESTPHALIA (1648): THE BIRTH
OF THE MODERN INTERNATIONAL SYSTEM
Background
The Treaty of Westphalia concluded the Thirty Years’ War and marked a turning point in
European and global diplomatic history. It ushered in the legal principles of territorial
sovereignty and state autonomy.
Page 1 of 35
,The Peace of Westphalia and Sovereignty
Learning Objective
Explain the significance of the Peace of Westphalia on European politics and diplomacy.
Key Points
The Peace of Westphalia was a series of peace treaties signed between May and October
1648 in the Westphalian cities of Osnabrück and Münster. The treaties ended the Thirty
Years’ War and the Eighty Years’ War.
The Thirty Years’ War was a series of wars in Central Europe between 1618 and 1648.
Initially a war between various Protestant and Catholic states in the fragmented Holy
Roman Empire, it developed into a conflict involving most of the great powers.
The Eighty Years’ War, or Dutch War of Independence (1568–1648), was a revolt of the
Seventeen Provinces against the political and religious hegemony of Philip II of Spain,
the sovereign of the Habsburg Netherlands.
According to the Peace of Westphalia, all parties would recognize the Peace of Augsburg
of 1555; Christians of non-dominant denominations were guaranteed the right to practice
their faith; and the exclusive sovereignty of each party over its lands, people, and agents
abroad was recognized.
Multiple territorial adjustments were also decided.
The Peace of Westphalia established the precedent of peace reached by diplomatic
congress and a new system of political order in Europe based upon the concept of co-
existing sovereign states. The Westphalian principle of the recognition of another state’s
sovereignty and right to decide its own fate rests at the foundations of international law
today.
The European colonization of Asia and Africa in the 19th century and two global wars in
the 20th century dramatically undermined the principles established in Westphalia.
Terms: cuius regio, eius religio
Page 2 of 35
,A Latin phrase that literally means “Whose realm, his religion,” meaning that the religion of the
ruler was to dictate the religion of those ruled. At the Peace of Augsburg of 1555 the rulers of the
German-speaking states and Charles V, the emperor, agreed to accept this principle.
The Eighty Years’ War
A revolt, known also as the Dutch War of Independence (1568–1648), of the Seventeen
Provinces against the political and religious hegemony of Philip II of Spain, the sovereign of the
Habsburg Netherlands.
The Thirty Years’ War
A series of wars in Central Europe between 1618 and 1648. Initially a war between various
Protestant and Catholic states in the fragmented Holy Roman Empire, it gradually developed into
a more general conflict involving most of the great powers.
The Peace of Westphalia
A series of peace treaties signed between May and October 1648 in the Westphalian cities of
Osnabrück and Münster. The treaties ended the Thirty Years’ War (1618–1648) in the Holy
Roman Empire and the Eighty Years’ War (1568–1648) between Spain and the Dutch Republic,
with Spain formally recognizing the independence of the Dutch Republic.
Westphalian sovereignty
The principle of international law that each nation-state has sovereignty over its territory and
domestic affairs, to the exclusion of all external powers, on the principle of non-interference in
another country’s domestic affairs, and that each state (no matter how large or small) is equal in
international law. The doctrine is named after the Peace of Westphalia, signed in 1648.
Peace of Augsburg of 1555
A treaty between Charles V and the forces of the Schmalkaldic League, an alliance of Lutheran
princes, on September 25, 1555, at the imperial city of Augsburg, in present-day Bavaria,
Page 3 of 35
, Germany. It officially ended the religious struggle between the two groups and made the legal
division of Christendom permanent within the Holy Roman Empire.
Introduction
The Peace of Westphalia was a series of peace treaties signed between May and October 1648 in
the Westphalian cities of Osnabrück and Münster. The treaties ended the Thirty Years’ War
(1618–1648) in the Holy Roman Empire and the Eighty Years’ War (1568–1648) between Spain
and the Dutch Republic, with Spain formally recognizing the independence of the Dutch
Republic. The peace negotiations involved a total of 109 delegations representing European
powers. The treaties did not restore peace throughout Europe, but they did create a basis for
national self-determination.
Background: Wars in Europe
Two destructive wars were the major triggers behind signing the eventual Peace of Westphalia:
the Thirty Years’ War in the Holy Roman Empire and the Eighty Years’ War between Spain and
the Dutch Republic.
The Thirty Years’ War was a series of wars in Central Europe between 1618 and 1648. Initially a
war between various Protestant and Catholic states in the fragmented Holy Roman Empire, it
gradually developed into a more general conflict involving most of the great powers. The war
began when the newly elected Holy Roman Emperor, Ferdinand II, tried to impose religious
uniformity on his domains, forcing Roman Catholicism on its peoples. The northern Protestant
states, angered by the violation of their rights to choose granted in the Peace of Augsburg,
banded together to form the Protestant Union. These events caused widespread fears throughout
northern and Central Europe, and triggered the Protestant Bohemians living in the dominion of
Habsburg Austria to revolt against their nominal ruler, Ferdinand II. They ousted the Habsburgs
and instead elected Frederick V, Elector of Palatinate, as their monarch. Frederick took the offer
without the support of the union. The southern states, mainly Roman Catholic, were angered by
this. Led by Bavaria, these states formed the Catholic League to expel Frederick in support of the
emperor.
Page 4 of 35
