Whether Marx and Engels jointly or Engels alone originated dialectical materialism, there can be no doubt that only Engels should be credited with its codification. This was recognized implicitly by both Plekhanov and Lenin, for they based their accounts of what they regarded as the Marxian philosophy on the works of Engels, above all, Anti-Dühring and Ludwig Feuerbach. They adopted this course because they believed—and impressed this belief upon the world—that there was a complete identity of views between Marx and Engels on all philosophical matters. As far as the conception of materialism is concerned, this meant in fact the substitution of Engels’ views for those of Marx.