The Articles of Confederation were ratified in 1781.
The Articles served as the first constitution of the United States. The Continental Congress adopted them on November 15, 1777, but they did not take effect until March 1, 1781, when Maryland became the last state to approve them.
The document created a confederation of states and gave Congress authority over diplomacy, war, and western territories. However, the national government could not impose taxes directly, regulate interstate commerce effectively, or easily enforce its decisions. Each state retained substantial power.
These weaknesses helped prompt the Constitutional Convention of 1787. The U.S. Constitution replaced the Articles after ratification and took effect in 1789. A common mix-up is to identify 1777 as the ratification year; that was the year Congress adopted the Articles, while 1781 marks their final approval and implementation.