 The Allied forces captured Somalia in February, Eritrea in March–April (after the decisive Battle of Keren), and Addis Ababa, capital of Ethiopia, in April.The Duke of Aosta, viceroy of Italian East Africa, surrendered at Amba Alagi in May.Forces in Italian East Africa were somewhat cut short by the Regia Aeronautica's forced presence in the Battle of Britain at the time, leaving only 150 planes in Ethiopia, as well by the impossibility of receiving supplies from Italy.