Marx's letter written to Pierre Joseph Proudhon (in Paris), asking him to join the Communist League.

Brussels, May 5, 1846

Dear Proudhon:

Since I left Paris I have often thought of writing to you, but circumstances beyond my control have prevented me from doing it. Please believe me that overbusyness and vexations connected with moving to another house are the only reasons for my silence.

And now in media res. Together with two of my friends, Frederick Engels and Philippe Gigot (both of them in Brussels), I have organized a continuing Correspondence [Committee] with German communists and socialists not only for a discussion of scientific questions but also for a review of popular writings and socialist propaganda, as a means of using them in Germany. The main aim of our Correspondence, however, will be to bring German socialists in contact with French and English socialists, to inform foreigners about socialist movements in Germany and Germans in Germany about the progress of socialism in France and England. In this way, differences of opinion can come to light, and one can attain an exchange of ideas and impartial criticism. This is a step the socialist movement has to take in its literary expression in order to get rid of nationalistic limitations. And at the moment of action it is certainly extremely useful for everyone to be informed about affairs abroad as much as about those in his own country.

In addition to the communists in Germany, our Correspondence will also include German socialists in Paris and London. Our contacts with the English are already established; as to France, we all believe that we could find there no better correspondent than yourself. You know that the English and the Germans have hitherto honored you more than your own countrymen.

Thus you see that what is involved here is the creation of a regular Correspondence and to secure for it the means of following the socialist movement in various countries, to attain rich and manifold results which no individual could achieve by his own work alone.

Should you accept our proposition, the postage of the letters you will receive, as well as those which you forward to us, will be paid here, since the money collections in Germany are designed to cover the cost of the Correspondence.

The local address you would use is: M. Philippe Gigot, 8 rue Bodenbrock. This is also the address for letters sent from Brussels.

I need not add that this whole Correspondence must be kept in strictest secret on your part, since we have to be careful not to compromise our friends in Germany.

Please reply soon, and accept the assurance of my sincere friendship.

Your devoted