 He reigned over the prince Kongo Empire from 1509 to late 1542 or 1543.During this time Afonso I had an increasingly awkward relationship with Portugal.This relationship came to a head during the latter half of the 1520s when the Kongo slave trade was at its peak, a direct result of Portuguese traders violating the law of Afonso I concerning who could and who could not be sold as a slave.