These books laid the foundation for Marx and Engels's most famous work, a political pamphlet that has since come to be commonly known as "The Communist Manifesto". While residing in Brussels in 1846, Marx continued his association with the secret radical organisation League of the Just. As noted above, Marx thought the League to be just the sort of radical organisation that was needed to spur the working class of Europe toward the mass movement that would bring about a working-class revolution. However, to organise the working class into a mass movement the League had to cease its "secret" or "underground" orientation and operate in the open as a political party. Members of the League eventually became persuaded in this regard. Accordingly, in June 1847 the League was reorganised by its membership into a new open "above ground" political society that appealed directly to the working classes. This new open political society was called the Communist League. Both Marx and Engels participated in drawing up the programme and organisational principles of the new Communist League.