In the late 19th century, after the Berlin conference had ended, European empires sailed with their armies to the Horn of Africa. The imperial clouds wavering over Somalia alarmed the Dervish leader Mohammed Abdullah Hassan, who gathered Somali soldiers from across the Horn of Africa and began one of the longest anti-colonial wars ever. The Dervish State successfully repulsed the British empire four times and forced it to retreat to the coastal region. As a result of its successes against the British, the Dervish State received support from the Ottoman and German empires. The Turks also named Hassan Emir of the Somali nation, and the Germans promised to officially recognize any territories the Dervishes were to acquire. After a quarter of a century of holding the British at bay, the Dervishes were finally defeated in 1920, when Britain for the first time in Africa used airplanes to bomb the Dervish capital of Taleex. As a result of this bombardment, former Dervish territories were turned into a protectorate of Britain. Italy similarly faced the same opposition from Somali Sultans and armies and did not acquire full control of parts of modern Somalia until the Fascist era in late 1927. This occupation lasted till 1941 and was replaced by a British military administration.
In what year did the British defeat the Dervishes?
1920

Hiberni (Ireland), Pictish (northern Britain) and Britons (southern Britain) tribes, all speaking Insular Celtic, inhabited the islands at the beginning of the 1st millennium AD. Much of Brittonic-controlled Britain was conquered by the Roman Empire from AD 43. The first Anglo-Saxons arrived as Roman power waned in the 5th century and eventually dominated the bulk of what is now England. Viking invasions began in the 9th century, followed by more permanent settlements and political change—particularly in England. The subsequent Norman conquest of England in 1066 and the later Angevin partial conquest of Ireland from 1169 led to the imposition of a new Norman ruling elite across much of Britain and parts of Ireland. By the Late Middle Ages, Great Britain was separated into the Kingdoms of England and Scotland, while control in Ireland fluxed between Gaelic kingdoms, Hiberno-Norman lords and the English-dominated Lordship of Ireland, soon restricted only to The Pale. The 1603 Union of the Crowns, Acts of Union 1707 and Acts of Union 1800 attempted to consolidate Britain and Ireland into a single political unit, the United Kingdom of Great Britain and Ireland, with the Isle of Man and the Channel Islands remaining as Crown Dependencies. The expansion of the British Empire and migrations following the Irish Famine and Highland Clearances resulted in the distribution of the islands' population and culture throughout the world and a rapid de-population of Ireland in the second half of the 19th century. Most of Ireland seceded from the United Kingdom after the Irish War of Independence and the subsequent Anglo-Irish Treaty (1919–1922), with six counties remaining in the UK as Northern Ireland.
Who foreign group conquered Britain around AD 43?
Roman Empire

After having declined in size following the subjugation of the Mediterranean, the Roman navy underwent short-term upgrading and revitalisation in the late Republic to meet several new demands. Under Caesar, an invasion fleet was assembled in the English Channel to allow the invasion of Britannia; under Pompey, a large fleet was raised in the Mediterranean Sea to clear the sea of Cilician pirates. During the civil war that followed, as many as a thousand ships were either constructed or pressed into service from Greek cities.
What was the driving force behind the revitalization of the Roman naval forces?
to meet several new demands