Back when the Christian church was formed in the first century, there were no church buildings. Believers met in homes and later in secret. Eventually city churches developed, where every believer from a city met in the same church. Each church had its own leadership, but all were under the authority of the Apostles. After the apostles all died, their writings were what guided the church. Eventually the Bible was formed from these writings.
After several centuries some city churches became more powerful, because the city they were located in was larger. Eventually, there were four powerful churches that all the other churches looked to: Jerusalem, Damascus, Rome and Constantinople. The churches in the East were closer together and so when they had disputes they looked to Rome to answer their disputes. Thus, the Roman Church became very powerful and influential. A great deal of politics were involved with the kings and leaders of the various countries too, but eventually, the Roman Catholic Church was formed (Catholic means universal). Along with this move came some doctrines that were not found in the apostles teachings, like paying of indulgences, worshiping of saints, canonizing saints, confessions to the priests, and a host of other beliefs.
By the seventh century, there weren’t that many Bibles and the Church leaders had access to them. The Bible wasn’t in the language of the people, so only the priests could read the Word of God and interpret it to the people. This made the Church even more powerful.
Eventually there were several priests which believed that some of the doctrines of the Catholic Church were in error. Some of these included the paying of indulgences and salvation by grace, not by works. John Hus was one of the first that was burnt at the stake for trying to correct the wrong doctrines in the Catholic church. Among others that protested these beliefs was Martin Luther. He nailed 95 objections to the door of the Church and got into a great deal of trouble. These various “protesters” (later to be called Protestants) eventually broke away from the Catholic Church and the power associated with it, and formed various protestant denominations. This is a nutshell version of what happened.
Many people are either Protestant or Catholic by tradition only. This means that they are Catholic or Protestant because their families are. But, what is important is the person’s friendship with God. There are many professing Catholics and Protestants who don’t know God, even though they go to Church often. They go out of tradition, rather than because of the relationship with the living God. It does not matter to God what Christian denomination a person belongs to, but rather whether or not a person knows God personally. For a brief presentation of the four principles that govern our friendship with God, please visit www.greatcom.org/laws.