These pieces tell us how religious beliefs developed in a number of ways. The book of Acts brings about the origin of Christianity in that the disciples of Jesus gathered in Jerusalem and were taken over by the spirit, which enabled them to speak in tongues and this attitude behind them, the disciples began a missionary campaign and converting people to believe in Jesus and from this Christianity was born. Early Christians were mixed in their knowledge, beliefs and even how they perceived Christ therefore emergence of different Christian denominations in the universe.
For the Islam, it was the end of Muhammad, who brought about the split between Sunnis and Shias. The Shias believed that Muhammad son Hussein should succeed him while the Sunnis supported Ali; both died at the battled field and it was the last moment of Hussein, that hold so much spiritual power for the Shia and the Shia named their leaders Imam. This has brought about the differences in the two Islam groups since the Sunnis read the Imams given to set a divine power, which is a serious sin. Hence, this split was the beginning of the two groups of Islam religion.
The development of Christianity and Islam is more complicated than I thought before reading this article. For example, I thought Christianity was just a unified change brought about by the existence of Christ, but here we are told on the diversities of the Christian faith, which becomes even more complicated. Some people believed in just the death of Christ that signified rise of Christianity, while others viewed Christianity in the teachings of Christ and with the explosive of Christian churches in many places; one cannot imagine that all places around the globe, everybody was doing and believing the same thing. Here, it becomes more difficult.
For the Islam, is even more complicated since as illustrated from the given sources that its War and conflicts between two sides that lead to the development of the Sunni and Shia Islam groups. It is difficult to imagine that war lead to development of these two Islam groups. The information from the history of the war makes it even hard to understand their beliefs.
When Assessing religions theologically is not so much complicated like when assessing religion historically because completely not clear and sometimes it may get distorted unlike assessing it theologically since information given was based on believes of people which is a simpler case.
The pieces illustrate this difference in that, for the Christians theologically, they belief in Christ and they have a unified movement. This is also the case with Islam. They believe in One God. Historically, a lot of information of various churches of Christians and how diverse their origin was dug up and, this makes it more complex for Islam. The pieces illustrate how the two groups went to war because of succession and the divine powers of Imams; this makes an individual view them from a different perspective and maybe notes that they two are different.