Omani-Zanzibari Sultanate, 1698

In 1698, the Imam of Oman army captured Fort Jesus in Mombasa and defeated the Portuguese. It was briefly captured by the Portuguese in 1728, but a year later was back under Omani rule and declared itself independent in 1746, although Oman did not recognise this; it restored its control in 1837. The flag of all the Sultanates, from Arabia to the East Africa coast, was plain red.