Troughout History, lifeforms developed into more and more sophisticated organisms, and often were more and more able to kick the living snot out of other lifeforms. Lets start with a little review. At one point, man got the idea that Fire was usefull. In fact, it was incredibly usefull, you could warm yourself with it, scare off big Fuzzy Animals with claws by it and process Big Fuzzy Animals with claws into small tasty Steaks through its truly divine intervention. This obviously raised the question "Where the Hell did that Fire came from?" The most direct awnser that various tribe around the earth got was: "It lives!", and "It has to be appeased!" This was the most likely origin of the first "House Gods". As civilisation developed, many more questions were asked. "Why does my neighbour catch more fish than I?" "Why does the sun go black sometimes?" "Why does the youth never listen to their elders?" "What the hell does Mightypeon want to say with this friggin wall of text?" To awnser this, many more gods were created, and to keep track of all of those Gods, a caste of priests or Shamans came into beeing. Lets call this "Look Look, my Tribe got a God!" Of course, the priests and shamans wanted to stay priests and shamans, meaning that travel, and the increasing contact to other civilisation in the antique times could have been a bit of a strain to their position. Naturally, they came to the easy solution, our gods are our gods, their gods are their gods, and if a particular gods of their looks fun to worship, we change his name a bit and worship him too. Smart souls usually said prayers to all known and unknown gods, and, while a Roman and a German of those times could come up with about 10 reasons to kill each other upon sight, religions was none of them. Then someone made an innovation: "My Tribes God is true, and all else are false!" Unfortunatly for the Midians, Khananites and various other people of the Near East, the Tribes of Juda took the task of cleansing their surroundings of unbelievers quite literally, however, ethnic cleansing happened before montheistic religions too, as a matter of fact, the clash between a nomadic society like the early tribes and and agrarian society like the Midians or Khananits had violence and genocide as the most usual outcome. Fortunatly for everyone else, Juda was not excatly a global power, and had next to no influence extending her borders. For time beeing, Germans, Celts and Romans continued to kill each other for more material reasons. After a while, the idea made a severy Jump. "My Tribes God is true, all else are false, and you can join my tribe by also saying that my tribes God is true!". While this may sound like a fairly convoluted sentence, it basically sums up the main difference between Christianity and Judaism, as far as non Christians/ non Jews are concerned. This idea was so appealing that, after a while, the Roman Empire thought that this idea may be usefull for empire building. A short while later, "My Tribes God is true, all else are false, and you can join my tribe by also saying that my tribes God is true! MK2" came on line, commonly known as Islam. The difference? Islam could be more aptly described with "My Tribes God is true, all else are false (some are falser than others), and you can join my tribe by also saying that my tribes god is true. If you prefer to use the outdated ""My Tribes God is true, all else are false, and you can join my tribe by also saying that my tribes God is true!"" Version, you are a Dhimmi and have to pay a Fee." This not only added the novel "Dont kill all unbelievers" aspect to religious warfare, it also indicated a signficant amount of commercial aptitude by the religion founder. No for a long while not much, apart from a very long and very bloody argument between the adherants of "My Tribes God is true, all else are false, and you can join my tribe by also saying that my tribes God is true!" and "My Tribes God is true, all else are false, and you can join my tribe by also saying that my tribes God is true! MK2", also known as the Crusades, happened. Then, at an age where religion founding was no longer exactly vouge, 2 new Ideas rose up. "My Tribe IS God, everyone else is false!" and "My Tribe Can become God, everyone else is false, but you can join us in our quest to do so!" Also non as Nationalism and Communism rose up. Immidiatly, both of those made quite a point of beeing not very kind to the adherants of earlier versions. Than they tried to kill each other, a conflict which "My Tribe Can become God, everyone else is false, but you can join us in our quest to do so!" won, largely due to not beeing as totally unforgiving as its competition. Due to beeing more interested in theorical discussion of "Becoming God" (also known as "reaching true Communism") than in supplying the population with needed things, "My Tribe Can become God, everyone else is false, but you can join us in our quest to do so!" lost towards a often encountered sentiment of "I dont care much about God anymore, lets get on with life". I hope a lot that "I dont care much about God anymore, lets get on with life" will eventually win the argument.