How did local East African rulers deal with Arab and Persian merchants in the 600s?

In the 600s, local East African rulers often engaged in trade relationships with Arab and Persian merchants, recognizing the economic benefits these exchanges brought. They established trade agreements and allowed merchants to set up trading posts along the coast, facilitating the exchange of goods such as gold, ivory, and slaves for textiles, spices, and other luxury items. While some rulers maintained autonomy and control over their territories, others formed alliances with these merchants, leading to cultural exchanges and the spread of Islam in the region. This interaction laid the foundation for the development of powerful coastal city-states like Kilwa and Mombasa.