The movement emerged in 1899 as European powers tightened their grip on the Horn of Africa. Hassan, educated in Qur’anic sciences and Islamic jurisprudence, condemned colonial interference and called for a revival of Islamic governance. His message resonated widely, attracting followers from numerous Somali clans. Hassan established a ruling council, the Khususi, composed of Sufi elders and advisers—including one from the Ottoman Empire—giving the movement both religious legitimacy and international connections.

Between 1899 and 1905, the Dervish Movement attracted around 25,000 youth from different clans, forming a formidable fighting force. They acquired firearms and launched their first major attack on the Ethiopian garrison at Jigjiga, securing cattle and an early victory that boosted morale. The Dervishes soon declared the British administration in Somaliland their primary enemy, prompting Britain to arm rival Somali clans to counter them.

The Dervishes fought a series of campaigns marked by mobility, deep knowledge of the terrain, and guerrilla warfare. After suffering losses in 1904, they reorganized into smaller units and continued their resistance. Their capital shifted over time—from Ilig (1905–1909) to Taleh (1913–1920)—reflecting both strategic adaptation and the pressures of colonial offensives. The Battle of Dul Madoba (1913) stands out as a major confrontation, demonstrating the movement’s resilience even as colonial forces intensified their efforts.

Hassan’s movement was not only military but ideological. It sought to expel British and Italian influence and defeat Ethiopian expansion, replacing foreign rule with an Islamic system grounded in Sufi doctrine. This vision helped lay the foundations for a broader Somali national consciousness.

By 1919, after two decades of conflict and the added strain of World War I, the Dervish state began to weaken. In 1920, a final British campaign—supported by airpower—destroyed the Dervish strongholds and ended the movement. Yet Hassan’s legacy endured. He is remembered as the “Father of the Somali People,” a symbol of unity, resistance, and cultural pride whose struggle continues to shape Somali identity.