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. Legacy 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 Somaliland, as well as other parts of the Horn region where the polity held sway. Archaeological excavations in the late 19th century and early 20th century at over fourteen sites in the vicinity of Borama in modern-day northwestern Somaliland unearthed, among other artefacts, silver coins identified as having been derived from Qaitbay (1468–89), the eighteenth Burji Mamluk Sultan of Egypt. Most of these finds are associated with the medieval Adal Sultanate. They were sent to the British Museum for preservation shortly after their discovery. In 1950, the British Somaliland protectorate government commissioned an archaeological survey in twelve desert towns in present-day Republic of Somaliland, near the border with Ethiopia. According to the expedition team, the sites yielded the most salient evidence of late medieval period affluence. They contained ruins of what were evidently once large cities belonging to the Adal Sultanate. Towns such as Awbare, Awbube, Amud, Abasa and Gogesa, featured between 200 and 300 stone houses. The walls of certain sites still reportedly stood 18 meters high. Excavations in the area yielded 26 silver coins, unlike the copper pieces that were more common in polities below the Horn region. The earliest of these recovered coins had been minted by Sultan Barquq (1382–99), also of the Egyptian Burji dynasty, and the latest were again Sultan Qaitbay issues. All of the pieces had been struck in either Cairo or Damascus. A few gold coins were also discovered during the expedition, making the area the only place in the wider region to yield such pieces. Besides coinage, high quality porcelain was recovered from the Adal sites. The fine celadon ware was found either lying on the surface, or buried at a depth of seven and a half inches, or ensconced within dense middens four to five feet high. Among the artefacts were grey granular sherds with a cracked blue-green or