The Articles of Confederation took effect as the United States' first constitution on March 1, 1781.
Congress completed the Articles on November 15, 1777, but the document required ratification by every state. Maryland was the final state to approve it, after disputes involving western land claims held up its ratification.
Maryland authorized ratification on February 2, 1781. Congress received confirmation of the state's assent on March 1, when the Articles officially became the governing framework of the United States.
The Articles created a confederation in which the states retained substantial sovereignty and the central Congress had limited powers. They were replaced by the Constitution on March 4, 1789. Thus, the drafting date, ratification date, effective date, and replacement date are four different milestones.