In the central part of the Mozambique territory, the Portuguese attempted to legitimise and consolidate their trade and settlement positions through the creation of ''prazos''. These land grants tied emigrants to their settlements, and inland Mozambique was largely left to be administered by ''prazeiros'', the grant holders, while central authorities in Portugal concentrated their direct exercise of power on, in their view, the more important Portuguese possessions in Asia and the Americas. Slavery in Mozambique pre-dated European-contact. African rulers and chiefs dealt in enslaved people, first with Arab Muslim traders, who sent the enslaved to Middle East Asia cities and plantations, and later with Portuguese and other European traders. In a continuation of the trade, slaves were supplied by warring local African rulers, who raided enemy tribes and sold their captives to the ''prazeiros''. The authority of the ''prazeiros'' was exercised and  upheld amongst the local population by armies of these enslaved men, whose members became known as ''Chikunda''. Continuing emigration from Portugal occurred at comparatively low levels until late in the nineteenth century, promoting "Africanisation". While ''prazos'' were originally intended to be held solely by Portuguese colonists, through intermarriage and the relative isolation of ''prazeiros'' from ongoing Portuguese influences, the ''prazos'' became African-Portuguese or African-Indian.