For many years Marx had laid aside his work on capitalism wher. ever he thought it necessary to refute the errors of his opponents. In the 1870s Engels assumed the mantle of defender of the Marxist faith. He explained that there was now a division of labour between Marx and himself. While Marx was writing "his great basic work", Engels was responsible for "the fight against opposing views".! Engels sacrificed his own researches in order to denounce the errors of Bakunin, Proudhon, Blanqui, Diihring, and Hochberg and to criticise the concessions made to the followers of Lassalle when the two German socialist parties united in 1875.