The Oromo Khaganate (Russian: оромо каганат; Oromo: Oromoo Kagnat) was a short lived confederation of various ethnic groups, though predominately Oromo, which grew to dominate the open grasslands of Southern Sudan and various parts of the Horn of Africa. It existed between 1891 and 1899 and was the product of several rogue Cossack bands from the nearby territories of Russian East Africa mingling with local peoples moving north to escape European dominance from the shorelines. A prominent cossack officer, Alexey Kaladin, proclaimed himself Khagan in 1891 after successfully uniting several tribes under his cossack deserters and sacking Sagallo in the winter of 1890.
From this position of strength the Oromo Khaganate wrought havoc across North-East Africa, extracting tribute from the governor of Italian Somalia, Vincenzo Filonardi, in 1893 and humiliating the Italian Empire. On its other periphery, the Oromo Khaganate swarmed into British-Egyptian Sudan where military operations continued until the death of Alexey Kaladin in 1898.
Following the death of Kaladin, the Khaganate began to splinter and though his successors attempted to continue his legacy the Oromo Cossacks faced a bitter defeat at the Battle of Rumbek on January 24, 1899. By spring the exhausted Khanate attempted to flee back into Somalialand where many of the leaders were captured and tried by Italian colonial officials following a further resounding defeat at Beledweyne.