Muslims believe in the holy war and observe the pilgrimage to Mecca which Christians neither believe in nor practice. During the Medieval period, both Christianity and Islam promulgated their religious beliefs and practices in territories where the majority existed. Christianity employed the use of missionaries whereas Islam employed offensive practices such as conquests, political rule and returning crusaders in spreading their faith (Spielvogel 238-243). 3. The expansion of trade The expansion of trade during the High Middle Ages resulted from developments in voyages of exploration by Vikings, growth of states, contacts with the Muslim world and the arrival of the Portuguese. Vikings exchanged goods as they sailed along trade centers in search of profit. The existence of various environmental zones and agricultural practices influenced trade to flourish. These resulted to the evolution of settlement as well as prosperity that in turn contributed to urbanization and the growth of states. In addition, contacts with Muslim merchants in the Trans Saharan trade involved the trade in kola nuts, gold, ivory, and slaves. The arrival of the Portuguese opened an outlet for West African manufactured products such as cloths. The utilization of Arab script and Muslim officials in complex bureaucracies remained as the impact of the expansion of trade on medieval society (Spielvogel 252-254). 5. The decline of papacy The papacy of the Roman Catholic Church had reached the peak of its power with the doctrine of temporal universal authority over secular rulers and fullness of power. However, the claims of temporal supremacy kept losing ground due to the growth of European secular monarchs. This created conflicts between papacy and the territorial states it never conquered.