Ancient trade networks and the diversity of Asia have been catalysts for the assimilation of diasporic cultures. Mingling of peoples has led to a cultural mosaic in the region. Trade routes that are older than colonization reveal the routes taken by the captives. But the borderline between descendants of captives and free migrants is not always easy to establish. The intersection of free and forced movement of Africans is memorialized in Janjira, an island base for African traders since the thirteenth century. From the sixteenth century onwards, Janjira became the power base for African rule of two Indian states until independence, when the princely states were merged. The first state was centred on Janjira and extended to the west coast of India (into today's Maharashtra). The second state consisted of scattered villages (in today's Gujarat) and was called Sachin.  
Social mobility followed conversion. Assimilation took place within the Islamic world, though the pattern of social mobility following conversion was also true of the Portuguese. Speaking Portuguese and conversion to Roman Catholicism were prerequisites for assuming a Portuguese identity. Conversion to Islam, learning Arabic and Arab lore, was a sine qua non for elite military slavery, which enabled Africans to make the transition from enslavement to positions of power and authority within a single generation. A few hundred Sidi elite remain to remind us of their past prominent political role, while the majority of Sidis were marginalized because of lack of patronage following political changes at independence.  
Diversity and acculturation have blurred demarcations between indigenous peoples and migrant Africans, and assimilation has further diluted ethnic and physiognomic differences. Asia is heterogeneous and complicated by the layered histories and intermingling of peoples and cultures. Dispersal of Africans to Asian lands is hidden by marginalization.