Siege of Saïo the Italian dictator, Benito Mussolini, proclaimed the colony of "Africa Orientale Italiana" (AOI, Italian East Africa), formed from Ethiopia (after the Italian victory in the Second Italo-Ethiopian War, fought 3 October 1935 – May 1936) and the existing Italian possessions of Italian Eritrea and Italian Somaliland. On 10 June 1940, Mussolini declared war on Britain and France, which made Italian military forces in Libya a threat to Egypt and those in Italian East Africa a danger to the British and French colonies in East Africa. Italian belligerence also closed the Mediterranean to Allied merchant ships and endangered British supply routes
Italian ironclad Formidabile December 1860, originally ordered by the Navy of the Kingdom of Sardinia. She was launched on 1 October 1861 and was completed in May 1862; by this time, the Sardinian fleet had been reformed as the "Regia Marina" (Royal Navy) of the newly unified Kingdom of Italy. In June 1866, Italy declared war on Austria, as part of the Third Italian War of Independence, which was fought concurrently with the Austro-Prussian War. The Italian fleet commander, Admiral Carlo Pellion di Persano, initially adopted a cautious course of action; he was unwilling to risk battle with the Austrian Navy, despite the