A specter is haunting Europe — the specter of Communism. All the powers of old Europe have entered into a holy alliance to exorcise this specter: Pope and Czar, Metternich and Guizot, French Radicals and German police spies.
The Communist Manifesto (1848), opening lines
Although Marx's choice of words here might make it seem that he was against communism, this was not the case.