Christian socialism was a movement in the 1800s by Protestants in Europe, especially Britain, calling for more government investigation and regulation to alleviate the disress of the poor, which they blamed on unrestrained capitalism. Supporters claimed that Socialism was compatible with Christianity as the early apostles in Jerusalem had all things in common (by private agreement, not because of government regulation). Their goal was to build God's Kingdom on earth. A few Americans joined the movement, although the Social Gospel was much more important in the U.S. in the era of the Third Great Awakening. The movement originated before Karl Marx and had little in common with Marxist socialism.
Critics accused social gospel preachers of focusing on this world rather than focusing on goal of saving souls. Christian socialists felt that they were doing God's will when they worked to improve conditions for their fellow human beings on Earth. Doing God's will would help to save souls. The Christian socialists formed a small part of the larger Social Gospel movement. It appealed to ministers and labor activists, but won few followers among actual workers.
Frederick D. Maurice (1805-72), a professor of theology at King's College London, until 1853, provided the initial leadeforship to a group who called themselves Christian Socialists, with The Kingdom of Christ (1838).
By 1870, Anglicans acknowledged that a 'theological transformation' had taken place which made the Incarnation central to Anglican thought. High Church organizations such as the Guild of St. Matthew, founded in 1877, embraced Maurice's theology of the Incarnation, and the Christian Socialists planned a new course for the church in its relations with society, social reform, and the rights of the working class.
Rev. Charles Kingsley (1819-75) played a leading role in the Christian Socialist movement in Britain in the mid-19th century; he was chaplain to Queen Victoria and later a canon of Westminster Cathedral. He explained that "Christian Socialism," meant cooperative enterprise and morality in social action. He published Politics for the People and The Christian Socialist. Kingsley, Anglican rector of Eversley in Hampshire, became the ardent and often controversial spokesman for the movement, and called on the upper classes to take part in this. His series in The Christian Socialist on 'Bible Politics' aimed to show that democracy is an idea from the Bible and is in the cause of God.
Gertrude Himmelfarb, a conservative historian, points out that "the generic form of Christian socialism ... was present among all the late-Victorian socialist groups, including the most radical of them." She notes that Keir Hardie, the late nineteenth-century trade unionist who became the first leader of the parliamentary Labour party early in the 20th century, described socialism as "the embodiment of Christianity in our industrial system." Himmelfarb finds that while these reformers tried to secularize religion, "that transference was rarely complete. What remained, for many socialists, was a spirit that transcended man, a moral idea rooted in religion which provided the ultimate rationale for socialism. Himmelfarb notes that a frequent complaint was that it appealed more to the upper class than the working class, or as one critic snapped, "Christian Socialism is the holy water with which the priest consecrates the heart-burnings of the aristocrat."
In Hungary, the Hungarian Christian Socialist Movement was active from 1895 to 1918, with ties to the agrarian movement and the Catholic People's Party; its leaders were theologian Ottokár Prohászka (1858-1928) and Sándor Giesswein (d. 1923), canon of Györ.
In the 21st century, the Christian Socialist Movement in England is a movement of Christians with a radical commitment to social justice, to protecting the environment and to fostering peace and reconciliation. It is holding a joint event on Cut The Carbon with Christian Aid at Labour Party Conference. Labour Party leader and former prime minister Tony Blair calls himself an 'ecumenical Christian' and has tied to Christian Socialism, though he led the Labour party to renounce its traditional commitment to government ownership of industry. "Christianity helped to inspire my rejection of Marxism," Blair explained. 
- Boyer, John. Culture and Political Crisis in Vienna: Christian Socialism in Power, 1897-1918. (1995) 702p. excerpt and text search
- Cort, John C. Christian Socialism: An Informal History. (1988) 402p
- Hopkins, Charles Howard. The Rise of the Social Gospel in American Protestantism, 1865-1915 (1940) (Chap. X "Christian Socialism") online edition
- Phillips, Paul T. A Kingdom on Earth: Anglo-American Social Christianity, 1880-1940. (1996) 303p.
- Charles Kingsley. The Works of Charles Kingsley (1899) 339 pages online edition
- Frances Eliza Grenfell Kingsley. Charles Kingsley: His Letters and Memories of His Life (1877) 502 pages online edition
- Gray, John. The Life of Frederick Denison Maurice: Chiefly Told in His Own Letters (1885) 707pp online edition