The origins of international law can be traced back thousands of years to ancient treaties like an agreement between the rulers of the city-state of Lagash, umma. The Roman Empire did not develop international law, yet the collapse of the Holy Roman Empire into independent cities, principalities, kingdoms, and nations paved the way for the development of international law. Later on,great writers like Grottius, the concept of the law of nature, and the theory of positivism made great contributions to the development of international law.

Define international law

International law is a set of those rules that are generally regarded and accepted as binding in relations between states and nations.

Different forms of general law

Modern point of view

From a modern point of view, relations between states are about the workings of an international law institution or organisation,their relations with one another, and their relations with states and individuals.

Sources of international law

Sources of international con be classified following two main kind;

Formal sources of international

Formal sources of international law means those sources from which the authority of law is derived. According to an opinion, the community of states is the formal source of international law.

Material sources of international law

Material sources of international law are those sources from which the subject matter of the law is derived.

Customs

Since time immemorial, states have entered into formal relations with one another. Over several ages,custom had been developed to conduct such relationships. custom had made modern international law. Therefore, customs are considered material sources of international law.

Treaties 

With the passage of time, customs have failed to meet the urgent demands of international society to regulate relations between states. In fact,international activities have become complex due to industrial and economic developments, technological advances, commercial law, and communication revolving.

In such situations,treaties play an important role not only in solving the complicated problems of the modern international community but also in developing international law. Treaties are considered a material source of international law.

Decisions of judicial or arbitral tribunals 

Decisions of courts and tribunals are considered subsidiary and indirect sources of international law. Article 38 of the Statute of the International Court of Justice provides that the court can apply judicial decisions as a subsidiary means for determining the rule of law. However, it reveals that decisions or arbitral tribunals are not only strictly speaking formal sources, but they are also regarded as authoritative evidence of the state of law in some instances.

Juristic work

Through the juristic work of various scholars of international law, the opinions of such scholars have been achieved and are widely admitted and used. Even such opinions sometimes lead to legislation under international law. Therefore, it would be fair to mention that the writings of such scholars have greatly influenced the development of international law. However,such writings are not mostly accepted as independent international sources.

Decisions of organs of international institutions

International institutions can represent intermediate or final steps in the evolution of customary rules. A resolution of institution can have full binding effect. Every institution has the inherent power to determine its own jurisdiction. Sometimes,such international institutions are given the power to make binding decisions. In this way, the decisions and determinations of the organs of an international institution can lead to the making of rules of international law.