The famous quote from Karl Marx that religion is the opium of the people is usually taken as an expression of the atheist nature of the communist movement. But Marx's activities as a communist actually began in a group called the League of the Just, founded by German workers in Paris in 1836 with the aim of "establishing the Kingdom of God on Earth, based on the ideals of love of one's neighbour, equality and justice". In 1847, the Communist League was created out of the League of the Just and the Communist Correspondence Committee of Bruxelles and, later that year, the new organisation issued the Communist Manifesto.
The thread of Christian Communism has continued from its 17th-century precedents such as the Plymouth Colony and the True Levellers through to the present day. It is based on the idea that the teachings of Jesus Christ compel Christians to support communism as an ideal social system.
A report from the Vatican that the founder of the Communist Party of Italy, Antonio Gramsci, converted back to Catholicism on his deathbed is, however, treated with a lot of scepticism in most quarters.