The rulers of the earlier Sultanate of Shewa and the Walashma princes of Ifat and Adal all possessed Arab genealogical traditions.
During Adal’s initial period, when it was centered on the port city of Zeila in present-day northwestern Somalia, the kingdom was primarily composed of Somalis, Afars and Arabs.
There is some debate over the ethnic composition of Adal after its capital moved to modern-day Ethiopia. I.M Lewis states:
Somali forces contributed much to the Imām’s victories. Shihab ad-Din, the Muslim chronicler of the period, writing between 1540 and 1560, mentions them frequently (Futūḥ al-Ḥabasha, ed. And trs. R. Besset Paris, 1897.). The most prominent Somali groups in the campaigns were the Samaroon or Gadabursi (Dir), Geri, Marrehān, and Harti – all Dārod clans. Shihāb d-Dīn is very vague as to their distribution and grazing areas, but describes the Harti as at the time in possession of the ancient eastern port of Mait. Of the Isāq only the Habar Magādle clan seem to have been involved and their distribution is not recorded. Finally several Dir clans also took part.
This finding is supported in the more recent Oxford History of Islam:
The sultanate of Adal, which emerged as the major Muslim principality from 1420 to 1560, seems to have recruited its military force mainly from among the Somalis.
Lewis, on the other hand, notes that the Imam’s origins are unknown. Ewald Wagner connects the name ʿAdäl with the Dankali (Afar) tribe Aḏaʿila and the Somali name for the clan Oda ʿAlï, proposing that the kingdom may have largely been composed of Afars. Although Afars constituted a significant part of Adal, Didier Morin notes that “the exact influence of the ʿAfar inside the Kingdom of `Adal is still conjectural due to its multi-ethnic basis.” Nevertheless, Franz-Christoph Muth identifies Ahmad ibn Ibrihim al-Ghazi as Somali.
According to the 14th-century historian Al-Umari, the people of Ifat spoke “Abyssinian and Arabic”. J.D. Fage suggests that the ‘Abyssinian’ in this assertion denotes an Ethio-Semitic language.
However, the 19th century Ethiopian historian Asma Giyorgis suggests that the Walashma themselves spoke Arabic, which is similar to Ge’ez.
During its existence, Adal had relations and engaged in trade with other polities in Northeast Africa, the Near East, Europe and South Asia. Many of the historic cities in the Horn of Africa such as Maduna, Abasa and Berbera flourished under its reign with courtyard houses, mosques, shrines, walled enclosures and cisterns. Adal attained its peak in the 14th century, trading in slaves, ivory and other commodities with Abyssinia and kingdoms in Arabia through its chief port of Zeila. The cities of the empire imported intricately colored glass bracelets and Chinese celadon for palace and home decoration.
The Adalite military was divided in several sections such as the infantry consisting of swordsmen, archers and lancers that were commanded by various generals and lieutenants. These forces were complimented by a cavalry force and eventually later in the empire’s history; by matchlock-technology and cannons during the Conquest of Abyssinia. The various divisions were symbolised with a distinct flag.
The Adalite soldiers donned elaborate helmets and steel-armour made up of chain-mail with overlapping tiers. The Horsemen of Adal wore protective helmets that covered the entire face except for the eyes, and breastplates on their body, while they harnessed their horses in a similar fashion. In siege warfare, ladders were employed to scale buildings and other high positions such as hills and mountains.
INVASION OF ABYSSINIA
In the mid-1520s, Imam Ahmad ibn Ibrihim al-Ghazi conquered Adal and launched a holy war against Christian Ethiopia, which was then under the leadership of Lebna Dengel. Supplied by the Ottoman Empire with firearms, Ahmad was able to defeat the Ethiopians at the Battle of Shimbra Kure in 1529 and seize control of the wealthy Ethiopian highlands, though the Ethiopians continued to resist from the highlands. In 1541, the Portuguese, who had vested interests in the Indian Ocean, sent aid to the Ethiopians in the form of 400 musketeers. Adal, in response, received 900 from the Ottomans.
Imam Ahmad was initially successful against the Ethiopians while campaigning in the Autumn of 1542, killing the Portuguese commander Cristóvão da Gama in August that year. However, Portuguese musketry proved decisive in Adal’s defeat at the Battle of Wayna Daga, near Lake Tana, in February 1543, where Ahmad was killed in battle. The Ethiopians subsequently retook the Amhara plateau and recouped their losses against Adal. The Ottomans, who had their own troubles to deal with in the Mediterranean, were unable to help Ahmad’s successors. When Adal collapsed in 1577, the seat of the Sultanate shifted from Harar to Aussa in the desert region of Afar and a new sultanate began.
After the conflict between Adal and Abyssinia had subsided, the conquest of the highland regions of Abyssinia and Adal by the Oromo (namely, through military expansion and the installation of the Gadaa socio-political system) ended in the contraction of both powers and changed regional dynamics for centuries to come. In essence, what had happened is that the populations of the highlands had not ceased to exist as a result of the Gadaa expansion, but were simply incorporated into a different socio-political system.
The Adal Sultanate left behind many structures and artefacts from its heyday. Numerous such historical edifices and items are found in the northwestern Awdal province of Somalia, as well as other parts of the Horn region where the polity held sway.
Archaeological excavations in the late 1800s and early 1900s at over fourteen sites in the vicinity of Borama in modern-day northwestern Somalia unearthed, among other artefacts, coins identified as having been derived from Kait Bey, the eighteenth Burji Mamluk Sultan of Egypt. Most of these finds are associated with the medieval Adal Sultanate, and were sent to the British Museum for preservation shortly after their discovery.