[3] According to legend, Ali ibn al-Hassan Shirazi was one of seven sons of a ruler of Shiraz, Persia, his mother was not ethnically habesha but rather a slave from the Land of Abyssinia.

[4] Setting sail out of Hormuz, Ali ibn al-Hassan, his household and a small group of followers first made their way to Mogadishu, the main commercial city of the East African coast.

A genetic study, published on March 29, 2023, confirmed the presence of significant Iranian-origin ancestry in the Y-chromosomal DNA of medieval inhabitants of the Swahili Coast, strongly supporting elements of the Persian-admixture narrative.

The acquisition of Sofala brought a windfall of gold revenues to the Kilwa Sultans, which allowed them to finance their expansion and extend their powers all along the East African coast.

At the zenith of its power in the 15th century, the Kilwa Sultanate owned or claimed overlordship over the mainland cities of Malindi, Lamu, Mwiini, Kismaayo, Inhambane and Sofala and the island-states of Mombasa, Pemba, Zanzibar, Mafia, Comoro and Mozambique (plus numerous smaller places) – essentially what is now often referred to as the "Swahili Coast".

[6] Kilwa also claimed lordship across the channel over the myriad of small trading posts scattered on the coast of Madagascar (then known by its Arabic name of Island of the Moon).

Despite its origin as a Persian colony, extensive inter-marriage and conversion of local Bantu inhabitants and later Arab immigration turned the Kilwa Sultanate into a veritable melting pot, ethnically indifferentiable from the mainland.

Nonetheless, the Muslims of Kilwa (whatever their ethnicity) would often refer to themselves generally as Shirazi or Arabs, and to the unconverted Bantu peoples of the mainland as Zanj or Kuffar ('infidels').

Kilwan traders encouraged the development of market towns in the Bantu-dominated highlands of what are now Kenya, Tanzania, Mozambique and Zimbabwe, where agricultural commodities such as grain and meat were exchanged for luxury goods and raw materials like gold and ivory.

The Kilwan mode of living was that of middlemen traders, who imported manufactured goods (like cloth and spices) from Arabia, India, and Persia, and exchanged them in the interior for agricultural products and precious raw materials, like gold and ivory.

Kilwan pilots were renowned for their extraordinary sailing accuracy, and Portuguese sailors marveled at their navigational instruments, particularly their latitude staves, which they considered superior to their own.

In its later years, the Sultans of Kilwa began falling into the hands of their ambitious ministers (viziers and emirs), who played the roles of kingmakers, and de facto rulers, and occasionally tried to foist themselves (or one of their family members) on the throne, in competition with the royal dynasty.

[citation needed] Throughout his long 'reign', Emir Muhammad fought an on-again and off-again battle with his nephew, Hassan ibn Suleiman (son of an earlier vizier).

Eventually, Emir Muhammad decided that, in the interests of constitutional propriety and civic peace, Kilwa sultans should always come from the royal dynasty, not families of viziers.

The man who succeeded to Muhammad's post, Emir Ibrahim (known as Mir Habrahemo in Barros, Abraemo in Goes), helped al-Fudail crush the ambitious Hassan once and for all in a great battle outside Kilwa.

Da Gama made contact with the Kilwa vassals of Mozambique, Mombassa and Malindi, seeking to secure their cooperation as staging posts for the Portuguese India Armadas.

In 1500, the 2nd Portuguese India Armada, under Pedro Álvares Cabral, visited Kilwa itself, and attempted to negotiate a commercial and alliance treaty with Emir Ibrahim.

Having secured separate treaties with Malindi, Mozambique and all-important Sofala, the Portuguese brought their menacing fleet to bear on Kilwa itself, and extorted a sizeable tribute from Emir Ibrahim.

It was in 1505 that Francisco de Almeida brought his fleet into the harbor of Kilwa, and landed some 500 Portuguese soldiers to drive Emir Ibrahim out of the city.

The Portuguese erected a fortress (Fort Santiago) on Kilwa and left a garrison behind, under the command of Pedro Ferreira Fogaça, to keep an eye on things.

In the chaos, streams of Kilwan residents fled the city, leaving it practically deserted, save for a handful of roving partisan gangs and the terrified Portuguese garrison.

Hearing of the Kilwan chaos all the way in India, the Portuguese viceroy Almeida dispatched a magistrate Nuno Vaz Pereira to inquire into the matter.

Pereira ruled in favor of Hussein, confirming him as sultan, but softened the blow by relieving the unpopular commander Fogaça and lifting the mercantilist restrictions on Kilwa shipping.