Final answer:
The establishment of Omani rule in the 18th century resulted in the expulsion of Portuguese forces from East Africa and the growth of Swahili culture.
Step-by-step explanation:
The establishment of Omani rule in the 18th century had significant consequences for the East African region. As the Omani Sultanate began to challenge Portuguese control, they successfully drove the Portuguese out of the region, including the Fort Jesus garrison at Mombasa. This marked the end of Portuguese dominance and control in East Africa, with the exception of Mozambique. The Omani rule also led to the growth of the Swahili culture and deepened trade connections with the Middle East and East and Southeast Asia.