The Articles of Confederation became effective on March 1, 1781, as the first constitution of the United States.
The Second Continental Congress approved the Articles in November 1777, but the document required ratification by all thirteen states. Maryland was the final state to ratify, ending the lengthy process and allowing the Articles to take effect.
The Articles created a loose confederation in which the states retained extensive power. Congress could conduct diplomacy and manage wartime affairs, but the central government lacked important powers such as a broad ability to tax individuals directly. These weaknesses later encouraged calls for a stronger federal system.
The Articles remained in force until the Constitution replaced them in 1789. The transition shows that American independence involved several constitutional stages, not just the Declaration of 1776. That institutional evolution is an important neighboring fact in the history remembered by America250.