Konstantin "Koča" Popović was a Serbian and Yugoslav politician and communist volunteer in the Spanish Civil War, 1937–1939 and Divisional Commander of the First Proletarian Division of the Yugoslav Partisans. He is on occasion referred to as "the man who saved the Yugoslav Partisans", because it was he who anticipated the weakest point in the Axis lines on the Zelengora–Kalinovik axis, and devised the plan for breaking through it during the Battle of Sutjeska, thus saving Josip Broz Tito, his headquarters and the rest of the resistance movement. After the war, he served as the Chief of the General Staff of the Yugoslav People's Army, before moving to the position of Minister of Foreign Affairs and spent the final years of his political career as Vice President of Yugoslavia.

Case Black, also known as the Fifth Enemy Offensive in Yugoslav historiography and often identified with its final phase, the Battle of the Sutjeska was a joint attack by the Axis taking place from 15 May to 16 June 1943, which aimed to destroy the main Yugoslav Partisan force, near the Sutjeska river in south-eastern Bosnia. The failure of the offensive marked a turning point for Yugoslavia during World War II. It was also the last major German-Italian joint operation against the partisans.