By the mid-19th century, rising Italian nationalism and calls for independence from foreign control led to a period of revolutionary political upheaval. After centuries of foreign domination and political division, Italy was almost entirely unified in 1861 following a war of independence, establishing the Kingdom of Italy as a great power. From the late 19th century to the early 20th century, Italy rapidly industrialised, mainly in the north, and acquired a colonial empire, while the south remained largely impoverished and excluded from industrialisation, fuelling a large and influential diaspora. Despite being one of the four main allied powers in World War I, Italy entered a period of economic crisis and social turmoil, leading to the rise of the Italian fascist dictatorship in 1922. Participation in World War II on the Axis side ended in military defeat, economic destruction and the Italian Civil War. Following the liberation of Italy and the rise of the Italian Resistance, the country abolished their monarchy, established a democratic Republic, enjoyed a prolonged economic boom, and became a highly developed country.