A treaty is a recorded international agreement between sovereign states or other subjects of international law (including international organizations) that is governed by international law. A treaty may also be known as an international agreement, protocol, covenant, convention, pact, or exchange of letters, among other terms; however, only documents that are legally binding on the parties are considered treaties under international law. Treaties may be bilateral (between two countries) or multilateral (involving more than two countries).
International agreements were used in some form by most major civilizations and became increasingly common and more sophisticated during the early modern era. The early 19th century saw developments in diplomacy, foreign policy, and international law reflected by the widespread use of treaties. The 1969 Vienna Convention on the Law of Treaties (VCLT) codified these practices and established rules and guidelines for creating, amending, interpreting, and terminating treaties, and for resolving disputes and alleged breaches.