There have been a handful of important historical rulers and world events that shaped why your family, your ancestors, and thus you, are christian today (of one sect or another). It may frighten some to actually research the history of their own religions in this way, because it goes against the very nature of the way most people think their "good news" should spread from one person to another. Most often, it has not been accepted freely with enthusiasm. It has been forced upon the masses by war, conquest, edict, threats of death/harm, through slave trades, by suppression of paganism, apostasy, other religions and any church criticisms by the ones who held the power, and manipulated and controlled through the education systems throughout the middle and dark ages and even the enlightenment periods. Here are just a few notable examples of why and how you are probably some form of a christian today (versus any of the other world religions):
Constantine: Constantine the Great (CE 272-337) was a supreme general and ruler who created the great Roman Empire that would last for a thousand years. Christianity until that point was a very minor religion followed by a few tribes and nomads in the post apostolic era. It wasn't until CE 311 that Galerius issued an edict that officially protected the early christians from religious persecution. Constantine was Galerius' successor and because of his mother's inclination to the faith, he expanded Galerius' edict with one of his own, the Edict of Milan, which again officially protected early christians but also allowed them to recover lost property previously confiscated by that persecution. This allowed early christianity to get a foothold and throughout the course of Constantine's reign, christianity was given preference over ancient Greek and Roman gods and eventually the roman orthodoxy, the state's official religion was established for the entire empire.
Constantine the Great - Wikipedia
Charles 'The Hammer' Martel: Charles Martel (CE 688-741) was a French political leader and a brilliant military strategist during a period of decline of the roman empire. He is credited with winning the Battle of Tours in 732 by defeating a powerful, invading Muslim army that sought to conquer and convert the whole of Western Europe to Islam. He is credited with single handedly saving the west and thus christianity from the hands of Abdul Rahman al Ghafiqi, as most experts believe no other european army at that time could have withstood the invasion had Martel's army failed. The Hammer is also well known for being the grandfather of another very important person in this list, Charlemagne.
Charles 'The Hammer' Martel - Wikipedia
Charlemagne: Charles the Great, or Charlemagne (CE 742-814) was a french king and emperor of the Roman Empire from 768-814. With his connections to the papacy, Charlemagne used his power to re-unify the roman empire and expand christianity, with wars against the italians, spanish, bavarians, slavs and saxons among others, converting or killing all. It was under his rule that the roman orthodoxy really took over as a major power again in europe, this time monasteries controlled a renaissance period. Charlemagne is credited with leading a revival of learning, the arts and culture, knowing that an educated citizenry would lead to a much stronger empire. But it was only through the church that anyone could learn, and thus christianity was allowed to control the flow of information at that time and the power of the pope and regional pontiffs grew exponentially.
Charlemagne - Wikipedia
The Crusades: Once the power of the roman empire had been re-established with Charlemagne, throngs of warriors had no wars to fight. With the increasing power of the roman church, the Pope used this free army to suppress muslim expansion as well as to restore christian access to the holy places in its texts. These were declared "Just Wars". In 9 series of crusades from CE 1095-1272, christian warriors attacked muslims, converting or killing those that stood in their way and pillaging cities they captured. The pope granted these warriors 'plenary indulgence', which basically means a reprieve from any sin conducted during the crusades in the name of the lord and the cause against the muslims.
The Crusades - Wikipedia
The Inquisition: The inquisition refers to a series of tribunals of the roman catholic church (CE 1231-1860) used to root our heretics, to get them to repent and conform or die in agony. This was certainly a way to get people en masse to follow a particular religion. Fear of torture or death.
The Inquisition - Wikipedia
Mehmet the Conqueror: Mehmed II (CE 1432-1481) was sultan of the ottoman empire and presided over the fall of constantinople back to muslim hands from the roman christian empire. His empire was involved in various land conquests, and he is honored in Turkish lore, but he also had a very interesting take on the people he conquered. Unlike the christians who converted or killed those they came across, Mehmet the conqueror promoted tolerance of the religions of the people he conquered, thus allowing safe havens of christianity to exist in the arab world, by decreeing this in 1463:
"I, the Sultan Khan the Conqueror,
hereby declare the whole world that,
The Bosnian Franciscans granted with this sultanate firman are under my protection. And I command that:
No one shall disturb or give harm to these people and their churches! They shall live in peace in my state. These people who have become emigrants, shall have security and liberty. They may return to their monasteries which are located in the borders of my state.
No one from my empire notable, viziers, clerks or my maids will break their honour or give any harm to them!
No one shall insult, put in danger or attack these lives, properties, and churches of these people!
Also, what and those these people have brought from their own countries have the same rights...
By declaring this firman, I swear on my sword by the holy name of Allah who has created the ground and sky, Allah's prophet Mohammed, and 124,000 former prophets that; no one from my citizens will react or behave the opposite of this firman!"
Mehmet the Conqueror - Wikipedia
Early American Explorers: Once Europe's great powers established themselves (Portugal, France, Spain, England), they began to send out expeditions over the seas to find new trade routes to the orient to increase wealth for country and king (CE 1492-1700). Little did anyone know, there was a whole continent of natural resources and "savages" to plunder, convert, conquer and colonize. Many of the people who colonized the americas were religious puritans, seeking refuge for their own christian beliefs, especially after the reformation split catholic and protestant in Europe. The Puritan colonization (CE 1630-1800) meant that most of the new settlers were extremely orthodox in their religious views, thus setting the stage for the so-called "christian america" that we know today.
European Colonization of the Americas - Wikipedia
The Puritans - Wikipedia
Slave Trades & Missionary Expansion: As a corollary to the American colonization, the slave trade developed in Africa bringing african tribes people to the new world (CE 1441-1865), converting them to christianity and expanding missionary efforts to African as well as American natives.
African Slave Trade - Wikipedia
King James Bible: King James of England (CE 1566-1625) ultimately was responsible for spreading the christian word through the english translation of the bible in 1611. This allowed lower class individuals to be able to read the scriptures outside of the church. It is generally considered to be the most influential book in the world. There weren't many books that all people were allowed to read, the fact that the english translation of the bible was one of them, allowed the religion to grab further footholds on the commoners of the day.
King James Bible - Wikipedia
The Age of Enlightenment: Out of the dark ages came the age of enlightenment (CE 1650-1800), where much of europe was able to again focus on education, the arts, and culture. As with the enlightenment period during Charlemagne's time, this resurgence was made available, but ultimately heavily controlled and financed by the religious institutions, where much of the money, power and educational facilities were held. The result of this period led to the American Revolution and produced the first legitimate seeds of atheistic thinking by people like Denis Diderot and Thomas Paine, but ultimately the giants of the day, Isaac Newton, Mozart and others were heavily influenced by the church.
The Age of Enlightenment - Wikipedia
Just few important people and events in history are why most christians today are actually christians, as opposed to muslim, jewish, pagan or something else following any number of gods that have long since been moved to the shelves of mythology. Most people just go along with tradition, never questioning their beliefs because they trust what their parents teach them. I feel there should be a desire to know the real history of how their faith came about. You can feel good about a story and be comforted in your routines, and your parish, and your lifestyle, but there are some ugly truths that ultimately led you to believe what you claim to believe. These truths really tell an important side of the story to these types of dogmatic religions, they show how heavily influenced they can be by the hands of a select few with power. It hardly seems the work of some divine author when you look at the totality of it. The amount of people tortured and killed over it, the conquests, the inquisitions, the edicts of a handful of rulers and religious leaders.
It's a fascinating and truly eye opening tale and I encourage everyone to thoroughly research all aspects of their faith, including the history of it before deciding to commit all the way to it.
The History of Christianity - Wikipedia