A more lasting result of this formal relation was that Edward I and other Miskito rulers who followed him allowed the British to establish settlements and plantations within his realm, and issued the first land grants to this effect in 1742. British settlement concentrated especially in the Black River area, Cape Gracias a Dios, and Bluefields. The British plantation owners used their estates to grow some export crops and as bases for the exploitation of timber resources, especially mahogany. Most of the labor on the estates was supplied by African slaves and by indigenous slaves captured in Miskito and British raids into Spanish territory. By 1786, there were several hundred British residents on the shore and several thousand slaves, mostly African.