Karl Marx called the Communist League. Both Marx and Engels participated in drawing up the programme and organisational principles of the new Communist League. In late 1847, Marx and Engels began writing what was to become their most famous work – a programme of action for the Communist League. Written jointly by Marx and Engels from December 1847 to January 1848, "The Communist Manifesto" was first published on 21 February 1848. "The Communist Manifesto" laid out the beliefs of the new Communist League. No longer a secret society, the Communist League wanted to make aims and intentions clear to the general public
Ventotene Manifesto future wars. Vayssière notes that the manifesto is widely seen as the birth of European federalism. Spinelli (1907–86), a former Communist, became a leader of the federalist movement due to his primary authorship of the Manifesto and his postwar advocacy. The manifesto called for a break with Europe's past to form a new political system through a restructuring of politics and extensive social reform. It was presented not as an ideal, but as the best option for Europe's postwar condition. The most important assessment was the assertion that This statement was in contrast with the idea, then prevailing, that unity