What are the major factors of the rise of Islam during and after the life of Muhammad?
The most salient feature in the dramatic rise of Islam was the military conquests of Arabian Muslims. Muhammad set the tone by attacking caravans of pagan Arabs, whose rejection of the prophet, and Islam, forced Muhammad to flee from Mecca to Medina in 622 AD. By the time of his death 10 years later, Muhammad had conquered Mecca and most of the pagan tribes of Western Arabia. He recruited soldiers in part through promising glory for their martyrdom, forced his captors to accept Islam, and systematically destroyed their pagan temples and religious artifacts.
After Muhammad's death in 632, his first four successors, or caliphs, continued military campaigns that quickly captured most of the middle east and spread into Europe. Though the victors did not force their new subjects to convert to Islam, they required them to pay a special tax to be able to practice any different "Abrahamic" faith (e.g., Christianity or Judaism). Since the majority of the conquering armies were already Islamic, there was also considerable social pressure to convert to the new regime's religion. Moreover, it is instructive to note that the Qur'an (Islamic bible) contains several passages urging Muslims to ultimately "fight" and "slay" non-believers.
Military conquest, of course, was not the only major factor in the spread of Islam. Traders passing through Arabia heard of the new religion, and helped spread it to their homelands. And, as with the growth of Christianity, pilgrims set out from Arabia to carry the word to peoples throughout the Mediterranean world. One could presume that there was an inherent appeal in the message of Islam that attracted a devout following. Perhaps, in an historically unstable and warring area of the world, having powerful conquerors who provided relative stability inspired confidence in their new leaders, and eventually the religion they brought with them.
Islam spread incredibly quickly during the life of Muhammad and shortly after his death. This can be attributed to a number of factors. Let us look at some of the major ones.
Muhammad gained his original core of followers by appealing to the disenfranchised population of Mecca and the surrounding region in western Arabia. He argued that his religion had a place for the poor and wealthy alike. This appealed to many people in Arabia who had been repeatedly exploited at the hands of the wealthy merchants, who often used the polytheistic religions of the region to exert control.
It was in the century after the death of Muhammad that Islam truly began to spread. This is the result of two main factors: conquest and trade.
The caliphates of the Umayyads and the Abbasids dynasties conquered vast swaths of land in the seventh and eighth centuries. They encouraged the people in these newly conquered lands to convert to Islam. By the latter part of this period, Islam was no longer solely associated with Arab identity; it became the identity of an entire region that stretched from India to Morocco.
Arabs had long been successful traders. As they carried their goods far beyond Arabia, they also brought their religion with them. As such, they found converts along their trade routes. Popular ports such as Malacca and Sumatra became Muslim hotspots. The converts there helped spread Islam to even more distant ports. This process rapidly spread Islam around South and Southeast Asia through the effort of Muslim merchants.
There are a number of factors that could help to account for the rise of Islam in the time during and soon after the life of Muhammad.
First, we have to assume that the content of the religion itself had something to do with its spread. The theology of the religion and its emphasis on monotheism and community must have been appealing to people in the areas that it came to dominate.
Second, the location of Saudi Arabia was important. This was a crossroads for trade. Because of that, the ideas of Islam could spread with traders and come to appeal to those in neighboring areas.
Finally, the military prowess of the Muslim armies had something to do with the spread of the faith. The armies were able to conquer far and wide and that enabled them to spread their religion to far off areas.