Vienna Convention on the Law of Treaties
Treaties are among the earliest manifestations of international relations, with the earliest known example dating to the mid-13th century BC, and are today recognized as a primary source of international law. 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, amending, and interpreting treaties, as well as for resolving disputes and alleged breaches. However, most treaties have internal procedures and mechanisms governing potential disagreements.