Definition, Evolution and Scope of International Law

In this age of equality and mutual collaboration and peaceful co-existence, no state can have an independent and secluded existence. All the states are related to one another in variety of ways. Every state has its relations with the other states of the world. The laws which regulate the dealings of the states with one another are called International Laws.

Definitions of International Law:

(1) In the words of Wheaton, “International law consists of those rules of conduct which reason deduces as consonant to justice from the nature of the society existing among independent nations; with such definitions and modifications as may be established by general consent”.

(2) R.N. Gilchrist maintains, “International Law is the body of rules which civilized states observe in their dealings with each other. These rules being enforced by each particular state according to its own moral standard or convenience”.

(3) In the words of T.J. Lawrence, “Rules which determine the conduct of the general body of civilized states in their mutual dealings”.

Evolution of International Law:

International Law is of very recent origin. The development of International Law IS the result of the development of international relations. In his famous book, international Law’, Professor T.J. Lawrence, who has made a special study of its decent developments, has divided it into three periods.

The first period begins with the origin of the European civilization and lasts till the beginning of the Roman Empire. The second period begins from the Roman Empire and lasts to the Reformation. The third extends from 1648 up to the present time.

First Period:

India was aware of much of international law when the rest of the world was in uncivilized stage. References have been made to these rules in ‘Koutilya’s Arthshastra’. For example, in the post-Vedic period there existed certain rules according to which wars were declared, and waged, treaties were renounced, alliances were negotiated and ambassadors were accredited Ambassadors were not to be killed, because it were they who gave the message of their rulers to the foreign rulers.

They were never convicted whether disclosed good messages or bad ones. Indian Rulers observed a regular code of war. References have been made to these rules in the Mahabharata and in other books of ancient times.

In the third century B.C., Rhodes, a famous city of Greece, became a very great trade centre. The traders of Rhodes started following certain rules which later on began to be observed by the other states of Greece. These rules are known as Maritime Code. They also recognised “the law of mankind” which established a system of the protection of envoys, obligations of alliances and sanctity of treaties

With the dawn of Roman Empire, Rome established its relations with the alien states. They also developed a system for dealings with the alien states. This system is known as Jus gentium which means law of nations. The Jus gentium is the real contribution of Rome in the development of International Law.

The Jus gentium was a Code of rules applied to the dealings with the citizens of different nations. This code of rules is very similar to the International Law. This is the greatest contribution of Rome to the development of International Law.

Second Period:

There was no development in the International Law so long as the Roman Empire existed. The theory of common superior (supreme) over all political units of the world was popular. After the fall of Roman Empire Feudal states emerged. The feudal rulers protested against the supremacy of the church.

The concept of territorially independent state was brought in with the advent of feudal system. The supremacy of Pope was questioned. Pope’s interference in the internal matters of different states annoyed the European rulers. The rulers abolished the authority of Pope and organised nation-states.

Wars were declared by these nation-states against one another. The Church laid stress to carry out these wars in human ways. Ayala, the judge of Spanish Military Court; Mr. Genteel, a prominent figure of Italy; Suarge, the famous jurist of Spain and the political thinkers belonging to the latter half of sixteenth century maintained that the dealings between different States should be regulated by the Law of Reason. States should observe the Law of Reason while dealing with other states on international level.

Third Period:

The third period extends from the date of Reformation up to the present time. Hugo Grotius’s book, “On the Law of War and Peace” (1625), is a notable contribution of this period. This book reflects upon the cruelty of wars fought in sixteenth and seventeenth centuries. Hugo Grotius, the Dutch Scholar formulated the doctrine of International Law and analysed international practice m his book.

He laid stress on the two fundamental doctrines:

(a) All States are equally sovereign and independent.

(b) The jurisdiction of the state is absolute over its entire area. His book “On the Law of War and Peace” deals in detail with the international laws of war and peace. References have been made to these laws of war and peace in the Peace Westphalia (1648) which ended thirty years’ war.

International Law of which we are aware in modern times is essentially the product of this period. Wheateon and Oppenheim are more prominent among the political thinkers who have expressed their views on International Law.

Scope and Contents of International Law:


The scope of International Law is extended to all the free and independent nations. According to International Law all the states whether they are small or big enjoy the same status. “No principle of law”, said Chief Justice Marshall, “is universally acknowledged than the perfect equality of nations. Russia and Geneva have equal rights. It results from this equality that no one can rightfully impose a rule on others”.


Following is the more comprehensive division of the contents of International Law:

(1) Laws governing states in times of peace.

(2) Laws governing states in times of war.

(3) Laws governing states in the relation of neutrality.

(1) Laws of Peace:

Laws of Peace include the rights and obligations concerning independence and equality of the states. They also include maritime code and navigation laws. They are the rules of intercourse of states.

They include the rights and duties of officials attached to foreign offices. They include privileges and facilities of the diplomatic representatives, organization and procedure international conferences and nature and method of treaty making, etc.

(2) Law governing states in times of war:

Rules of War form the large portion of International Law. The rules of war include the declaration of war, the classification of wars, laws and customs of war on land, sea and air, the after-effects of war, the dealings with war prisoners.

According to the laws, it is quite unconventional to use poisonous gases and bacteria’s in the warfare and to bombard the civil areas. These rules prohibit the states, engaged in war, from seeking foreign military assistance and from mining the ports.

(3) Law governing states in the relation of neutrality:

The laws of neutrality embrace the duties of belligerent states of neutral states, duties of neutral states to belligerent states, neutral trade, commerce, contraband and blockade, etc.

SAKHRI Mohamed
SAKHRI Mohamed

I hold a Bachelor's degree in Political Science and International Relations in addition to a Master's degree in International Security Studies. Alongside this, I have a passion for web development. During my studies, I acquired a strong understanding of fundamental political concepts and theories in international relations, security studies, and strategic studies.

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