Confederation, in political terminology, a union of sovereign states each of which is free to act independently. It is distinguished from a federation, in which the individual states are subordinate to the central government.
Confederations existed in ancient times, notably the Delian League, formed under Athenian leadership in the 5th-century bc to resist Persian aggression, and the Achaean and Aetolian leagues of the 4th, 3rd, and 2nd centuries bc, which were prominent in the Hellenistic world.
In modern times the term confederation is applied to a joining together of formerly independent states to create a single political unit. During the American War of Independence, the former colonies set up a confederation and stated its purposes in the Articles of Confederation. After experience had demonstrated that this form of organization was too weak, the position of the Federalists, who argued that the former colonies should form a federation, was embodied in the United States Constitution. The southern states that seceded in 1861, believing that the federal union impinged on the sovereignty of the several states, formed themselves into a confederation, the Confederate States of America.
Several short-lived attempts at confederation appeared in 19th-century Europe, such as the Germanic Confederation established by the Congress of Vienna in 1815 after the downfall of Napoleon, and the North German Confederation of 1866-1870, a transitional organization preceding the establishment of the German Empire.