Columna Durruti
When the Spanish Civil War broke out, Marzani left Oxford to participate as a volunteer in the Spanish Republican Army. He served with the Durruti Column, a unit of the anarchist wing of the Republican forces, during late 1936 and early 1937. His advocacy of military discipline raised suspicion that he was a Communist, and thereby an adversary of the anarchists in the Republican struggle. Slated for execution as a Communist threat to the anarchist unit, he left for Barcelona. In Spain, Marzani was impressed by what he had seen of the Communists, but not by the anarchists.