Further south in the central highlands, the primary commercial crop was cotton, and British and Portuguese cotton plantations displaced the native Ovimbundu.  Unlike the Bakongo farmers of the north who largely stayed together and settled in Zaire, the Ovimbundu dispersed in all directions, some remained in the area to work the cotton fields, while others migrated north to work on the coffee plantations or south to less populated areas.  The employment of Ovimbundu on land formerly occupied by Bakongo farmers created tensions between the two groups. 