Muslim conquests following Muhammad's death led to the creation of the caliphates, occupying a vast geographical area; conversion to Islam was boosted by missionary activities, particularly those of Imams, who intermingled with local populations to propagate the religious teachings.[1] These early caliphates, coupled with Muslim economics and trading and the later expansion of the Ottoman Empire, resulted in Islam's spread outwards from Mecca towards both the Atlantic and Pacific Oceans and the creation of the Muslim world.