The Afro-Portuguese were also heavily involved in the slave trade, which dominated nearly all economic activity in Angola prior to its abolition in the 1870s. At Berlin Conference of 1884-1885 the European powers divided most of Africa into zones of influence, as they competed for influence and dominance of the continent.  The so-called "scramble for Africa" was brought about by the industrialization of Europe and the need for both important natural resources and markets for finished industrial goods.  Like its neighbors and rivals, Portugal asserted its hold over its colonies in this period and began to develop and settle the interior.