The Black Legion (Croatian: Crna Legija), officially the 1st Standing Active Brigade (Prvi stajaći djelatni sdrug), was an Ustaše militia infantry unit active during World War II in Independent State of Croatia. The legion was formed in September 1941 as the 1st Ustaša Regiment. It consisted largely of Bosnian and Croatian refugees from eastern Bosnia, where large massacres were carried out by Chetniks and to a small degree by the Yugoslav Partisans. It became known for its fierce fighting against the Chetniks and the Partisans and massacres against Serb civilians. The legion's commanders were Colonel Jure Francetić and Major Rafael Boban and it consisted of between 1,000 and 1,500 trained mechanized infantrymen.