Mombasa travels to the Swahili Coast and made some mention of the city, although he only stayed one night. He noted that the people of Mombasa were Shãfi'i Muslims, religious people, trustworthy and righteous. Their mosques are made of wood, expertly built. The exact founding date of the city is unknown, but it has a long history. Kenyan school history books place the founding of Mombasa as 900 A.D. It must have been already a prosperous trading town in the 12th century, as the Arab geographer Al Idrisi mentions it in 1151. The oldest stone mosque in Mombasa, Mnara, was built
Mombasa was renamed as Mvita (in Swahili) or Manbasa (Arabic). Portugal attacked the city again in 1528. In 1585 a joint military expedition between the Somalis of Ajuran Empire and the Turks of Ottoman Empire led by Emir 'Ali Bey successfully liberated Mombasa and other coastal cities in Southeast Africa from the Portuguese colonizers. The Portuguese landlords; only Malindi remained loyal to Portugal. The Zimba overcame the towns of Sena and Tete on the Zambezi, and in 1587 they took Kilwa, killing 3,000 people. At Mombasa the Zimba slaughtered the Muslim inhabitants, but they were halted at Malindi by the Bantu-speaking