the first two pages of the treaty of brest-litovsk
, in (left to right) german, hungarian, bulgarian, ottoman turkish and russian
a treaty is a formal written agreement entered into by actors in international law, namely sovereign states and international organizations. a treaty may also be known as an international agreement, protocol, covenant, convention, pact, or exchange of letters, among other terms. regardless of terminology, only instruments that are binding upon the parties are considered treaties subject to international law.
treaties can be loosely compared to contracts, in that the parties willingly assume binding obligations among themselves, and any party that breaches its obligations can be held liable under international law. treaties vary significantly in substance and complexity, and may govern a wide variety of matters, such as territorial boundaries, trade and commerce, political alliances, and more.
international law on treaties have mostly been codified by the vienna convention on the law of treaties, which sets forth the rules and procedures for creating, enforcing, amending, and interpreting treaties. as one of the earliest manifestations of international relations, treaties are recognized as a primary source of international law.