The publisher Leske has just been to see me. He is bringing out a quarterly  in Darmstadt which is not subject to censorship. Engels, Hess, Herwegh, Jung and I, etc., are collaborating with him. He has asked me to solicit your cooperation -- poetry or prose. Since we must make use of every opportunity to establish ourselves in Germany, you will surely not decline. Of all the people I am leaving behind here, those I leave with most regret are the Heines. I would gladly include you in my luggage! Best regards to your wife  from mine and myself. Yours K. Marx
Letters: Letters: Marx to Heine, Feb 1845