During the medieval period, Somaliland and the rest of the Horn of Africa went through a number of important processes that laid the foundations of many of the historical dynamics of the 20th and 21st centuries in the region. These transformations included the consolidation of Islam, the expansion of international trade networks, the movement of the Somali people to the west, and the emergence of a score of Muslim principalities that progressively consolidated their control over significant territories and populations. Although the general outline of the period is well known through a number of Ethiopian, Arabian, and European texts, material evidence for this period is still scarce, especially in Somaliland where research had been discontinued until the 2010s due to political reasons.
Research conducted during the 2010s has shown the coexistence of a network of permanent settlements with a rich nomadic culture, expressed in coastal trading posts, inland gathering places, and funerary monuments. Permanent settlements varied widely in size and functions, but showed a remarkable uniformity in terms of architecture, urbanism, and material culture. Nomadic gathering sites, on the contrary, show significant differences but share a common feature: their role as fixed nodes in an otherwise fluid landscape, where groups of different backgrounds could interact safely. Both types of sites were deeply involved in a complex trade system that connected the Horn of Africa with the Arabian Peninsula, the Middle East, India, and China, with Somaliland playing a key role in the import, export, and transport of commodities and goods. Nomads, urban dwellers, and foreign merchants collaborated in the maintenance of this key economic activity that, unlike in other regions of east Africa, did not lead to the emergence of urban centers by the coast.
The western region of Somaliland shows clear similarities with nearby regions of Ethiopia, and was probably soon under the control or influence of the Muslim sultanates that ruled the region. On the contrary, the central region remained mostly a nomadic area until well into the 13th century. At this moment, the increase of trade around Berbera, the arrival of Islam, and the progressive influence of the Muslim states altered significantly the balance of the region, leading to the emergence of permanent settlements and deep changes in its social and economic parameters. Further to the east, the territory seems to have stayed a nomad’s land, far away from the Muslim states’ influence, although active relationships were established between the Somali clans and the Sultanate of Adal during the 15th and 16th centuries.
In the 16th century, the complex balance established in previous centuries suffered a series of major setbacks due to the disturbance of the maritime trade routes by the Portuguese, the defeat of the Sultanate of Adal against the Christian kingdom of Abyssinia, and the Oromo expansion from the south. The network of permanent settlements was almost completely dismantled and state structures disappeared in the region until the 20th century, with most of the population embracing the nomadic life that has become the traditional Somali lifestyle into the 21st century.