It was carried out by nomadic Arab or Turkish conquerors. And so that is a similar form method that we're talking about, though, in this map. In the Indian Ocean and West Africa, it spread by peaceful contacts among merchants or through the preaching of missionaries. In some cases, the diffusion of Islam depended on its adoption by local ruling families. In others, it appealed to urban classes of the population, or tribal communities. The question of why people convert to Islam has always generated intense feeling. Earlier generations of European scholars believed that conversion to Islam were made by the point of the sword, and that conquered peoples were given the choice of conversion or death.