During the revolutionary troubles in 1848 Marx returned to Germany, and along with his comrades, Engels, Wolff, etc., he supported the most advanced democracy in the _New Rhenish Gazette_. In 1849 he settled in London, where he spent his after-life in the elaboration of his economic views and in the realisation of his revolutionary programme. In 1859 he published _Zur Kritik der politischen Oekonomie_. This book was for the most part incorporated in the first volume of his great work on capital, _Das Kapital_, which appeared in 1867.[2] Much of his later life was spent in ill health, due to the excessive work by which he undermined a constitution that had originally been exceptionally healthy and vigorous. He died in London, March 14, 1883. It was a time of the year which had been marked by the outbreak of the Commune at Paris, and is therefore for a twofold reason a notable period in the history of the proletariat. Since the death of Marx his great work, _Das Kapital_, has been completed by the publication of the second and third volumes, which have been edited by Engels from manuscripts left by his friend. But neither of these two volumes has the historical interest which may fairly be claimed for the first. In 1877 Engels published on his own account a work called _Herrn Eugen Dührings Umwälzung der Wissenschaft_,[3] a controversial treatise against Dühring (a teacher of philosophy in the university of Berlin) which has had considerable influence on the development of the German Social Democracy. Engels died in 1895, after loyal and consistent service in the cause of the proletariat, which extended over more than fifty years. The causes which have variously contributed to the rise of German socialism are sufficiently clear. With the accession of the romanticist Frederick William IV. to the throne of Prussia in 1840 German liberalism received a fresh expansion. At the same time the Hegelian school began to break up, and the interest in pure philosophy began to wane. It was a time of disillusionment, of dissatisfaction with idealism, of transition to realistic and even to materialistic ways of thinking. This found strongest expression in the Hegelian left, to which, after the ideals of the old religions and philosophies had proved unsubstantial, there remained as solid residuum the real fact of man with his positive interests in this life. The devotion and enthusiasm which had previously been fixed on ideal and spiritual conceptions were concentrated on humanity. To adherents of the Hegelian left, who had been delivered from intellectual routine by the most intrepid spirit of criticism, and who therefore had little respect for the conventionalisms of a feudal society, it naturally appeared that the interests of humanity had been cruelly sacrificed in favour of class privilege and prejudice.