After the split on 1 September 1850, the history of the Communist League in London is virtually identical with that of the group around Willich and Schapper. Marx christened them ‘Willich-Schapper faction’ and ‘Sonderbund’ (Separatist League)—names adopted by historiography-to draw attention to his view that they were only the illegitimate offspring of the Communist League.1 But Willich and Schapper themselves agreed, as did most of their contemporaries, that the group was in fact the official continuation of the League. (The Prussian police deliberately ignored differences between the two factions, of course, for their own purposes.2) In London the great majority of League members (though a minority of the Central Authority) adhered to Willich and Schapper. Some 16 to 18 socialists regularly participated in the ‘Society of Dr Marx’, but their opponents, organised in four groups, could muster over three times as many adherents.3 The MarxEngels group transferred its Central Authority power to Cologne immediately after the split and as an organisation with regular sessions it survived in London for only four more months, until January 1851.4 Only when the defendants in the infamous Cologne trial urgently required outside help did the London group reconvene for the sole purpose of aiding them, finally dissolving in November 1852 directly after the verdict.5 The Willich-Schapper faction, on the other hand, were active for more than two years longer both in London and on the Continent, figuring prominently in police reports as its emissaries kept in touch with the Swiss, French and some German League groups and circles. Other London exile and Chartist societies had closer contacts with it than with Marx’s associates. It is therefore not surprising that Willich, not Marx, was the bestknown communist among the German exiles in London at the time.