The Mahdali dynasty emerged at Kilwa toward or at the end of the thirteenth century. Its rulers belonged to the Mahdali or Mahadila family, a clan of sayyids living in southwestern Yemen at the time. The dynasty was also known as that of Abu’l-Mawahib, “the father of gifts,” a sobriquet associated with its most famous ruler. Al-Hasan b. Talut, the first ruler of the dynasty, seized power with the assistance of people already resident at Kilwa rather than through an external invasion.

Al-Hasan’s accession appears to have broken the former dominance of Mafia over Kilwa. His son, Sulayman b. al-Hasan, was apparently killed while sultan, possibly by the Mafia faction in Kilwa. His own son, al-Hasan b. Sulayman, then took revenge upon the people of Mafia and defeated them. This victory helped establish Kilwa’s independence from the political connection associated with Mogadishu and opened the way for a more direct relationship with Aden.

The early fourteenth century was a period of marked prosperity at Kilwa. Stone construction increased, and a new architectural style introduced vaults and domes. The Great Mosque was substantially enlarged, more than doubling its area, while the palace and emporium known as Husuni Kubwa was constructed. An inscription in the building names al-Hasan b. Sulayman, probably the grandson of the dynasty’s founder and possibly the Abu’l-Muzaffar Hasan called Abu’l-Mawahib, whom Ibn Battuta visited around 1332.

Mahdali sultans issued coins in a style somewhat different from that of the preceding dynasty. The founder’s coins are very rare, perhaps suggesting a short reign, whereas those of Sulayman b. Hasan and al-Hasan b. Sulayman are common. Chinese imports increased greatly during this period, while Islamic wares became relatively uncommon and were mainly represented by pottery thought to have been produced in the Aden region, reinforcing the evidence for close ties with southwestern Arabia.

The dynasty’s power was closely connected with the gold trade of Sofala. Da'ud b. Sulayman is described as having become wealthy there before being summoned to rule Kilwa, while his son Sulayman Hasan is credited with controlling the trade and appointing governors at Sofala. The account attributes to Sulayman Hasan the construction of a stone fortress, walls, towers and elite houses at Kilwa, although the reported conquest of Pemba, Mafia and Zanzibar is explicitly treated as doubtful and may have been misplaced chronologically.

Kilwa appears to have declined somewhat during the latter part of the fourteenth century. The Kilwa Chronicle provides little information about the sultans, archaeological evidence records few new stone buildings, and coin minting ceased. The reasons for this decline remain obscure. Building activity revived in the first half of the fifteenth century on the neighboring island of Songo Mnara, while trade with the Persian Gulf became especially important and the connection with Aden continued.

During the middle of the fifteenth century, disputes over succession allowed the ruling family of Zanzibar to intervene, and Zanzibar appears to have gained considerable influence. By the end of the century, intrigues involving amirs and viziers weakened the sultanate further. Kilwa’s hold over its southern possessions and their commerce diminished, and the governor of Sofala had effectively declared himself independent by the time the Portuguese arrived. Control over Angoche and other towns north of Sofala may also have been affected, although their earlier subordination to Kilwa is itself uncertain.