Irish independence refers to the process by which Ireland gained sovereignty from British rule. This movement began in the early 20th century, culminating in the signing of the Anglo-Irish Treaty in 1921, which established the Irish Free State as a self-governing entity within the British Commonwealth. The treaty led to a civil war between pro- and anti-treaty factions, ultimately resulting in the consolidation of power by the pro-treaty side. In 1937, Ireland adopted a new constitution, further asserting its independence, and in 1949, it officially became a republic, fully severing ties with the British Commonwealth.