Marx was at the time engrossed in economic research and was unable to fulfill the commission, but on August 14, 1851 we wrote a letter asking his friend and co-thinker Frederick Engels to produce "a series of articles about Germany, from 1848 onwards." Engels agreed with this plan and over the next 13 months he went on to produce 19 articles on the 1848 German revolution for the New York press. Marx was closely consulted during the writing of this material and read over each manuscript before sending it for publication.