Arvid Harnack (German: [ˈaʁvɪt ˈhaʁnak] ; 24 May 1901 – 22 December 1942) was a German jurist, Marxist economist, Communist, and German resistance fighter in Nazi Germany. Harnack came from an intellectual family and was originally a humanist. He was strongly influenced by Johann Wolfgang von Goethe but progressively moved to a Marxist-Socialist outlook after a visit to the Soviet Union and the Nazis' appearance. After starting an undercover discussion group based at the Berlin Abendgymnasium, he met Harro Schulze-Boysen, who ran a similar faction. Like numerous groups in other parts of the world, the undercover political factions led by Harnack and Schulze-Boysen later developed into an espionage network that supplied military and economic intelligence to the Soviet Union. The group was later called the Red Orchestra (Rote Kapelle) by the Abwehr. He and his American-born wife, Mildred Fish, were executed by the Nazi regime in 1942 and 1943, respectively. Source: Wikipedia (en)