Vienna Convention on the Law of Treaties

Quick Facts: Who was Vienna Convention on the Law of Treaties?

Subject:

Vienna Convention on the Law of Treaties

Known for:

International law framework governing the drafting, interpretation, and validity of treaties between states.

Verified Source:

2Day Chrono-Wiki & Primary Historical Archives

Origins & Early Life

The Vienna Convention on the Law of Treaties (VCLT) is an international agreement that regulates treaties among sovereign states. Known as the "treaty on treaties", the VCLT establishes comprehensive, operational guidelines, rules, and procedures for how treaties are drafted, defined, amended, and interpreted. The VCLT defines a treaty as an international agreement in writing concluded between states governed by international law.

Career & Major Achievements

The Vienna Convention on the Law of Treaties was adopted and opened to signature on 23 May 1969, became effective on 27 January 1980, and has been ratified by 119 sovereign states as of May 2026. Non-ratifying parties, such as the U.S., have recognized parts of the VCLT as a restatement of customary international law. In treaty law, the VCLT is the authority for resolving disputes about the interpretation of a treaty.

Enduring Legacy & Impact

The VCLT definition of a treaty is not universally accepted. For instance, VCLT defines a treaty as between states, excluding non-state actors (such as international organizations). Treaties may also be defined differently under domestic law, as certain prerequisites have to be met for something to count as a treaty.

Chronological Milestones & Life Events

1. 1969: 1969 Milestone — The Vienna Convention on the Law of Treaties was adopted and opened to signature on 23 May 1969, became effective on 27 January 1980, and has been ratified by 119 sovereign states as of May 2026.

Notable Quotes by Vienna Convention on the Law of Treaties

“The VCLT is the authority for resolving disputes about the interpretation of a treaty.”

Historical Fact-Check Quiz: Vienna Convention on the Law of Treaties

True or False: “The Vienna Convention on the Law of Treaties defines a treaty as an agreement that can be concluded between any two international bodies, including non-state organizations.”

Answer (FALSE ❌): The VCLT specifically defines a treaty as an international agreement in writing concluded between sovereign states, thereby excluding non-state actors like international organizations.

Contemporary Figures & Related Historical Timelines

• Adam Gilchrist — Historical peer (Born in 1969) (1969): Legendary Australian cricketer, redefining the wicket-keeper-batsman role with aggressive flair.
• Adam Riess — Historical peer (Born in 1969) (1969): Astrophysicist known for evidence of accelerating universe expansion via supernovae.
• Abby Wambach — Historical peer (Born in 1980) (1980): Iconic American soccer forward, celebrated for her goal-scoring prowess and longevity.
• Adande Thorne — Historical peer (Born in 1980) (1980): Trinidadian-American YouTuber, animator, comedian, and actor known as Swoozie.
• Abdrabbuh Mansour Hadi — Historical peer (Died in 2026) (2026): Yemeni politician who served as the second President of Yemen from 2012 to 2022.
• Abdullah Ibrahim — Historical peer (Died in 2026) (2026): Pianist and composer, considered the leading figure in the subgenre of Cape jazz.

Frequently Asked Questions about Vienna Convention on the Law of Treaties