-Under Construction-Since before the dawn of civilization there have been aggressive nature-lovers of various kinds. Everyone who wasn't "civilized enough" was called a barbarian, and for a long time it was meant as an insult.
Well, technically, this is where all of humanity started out; living alongside the animals and plants, and just fighting over the normal amount of stuff for mammals to fight over. Everything was ok. Once enough homo sapiens stopped fully acting like other primates, they stopped being cavemen, and gained some human culture and beliefs. This is when they started being barbarians.
Having fire or a wheel really didn't change much, and neither did language. People continued to have these things and still be partially wild savages in every other way.
Then cities came, and everything started to change. To build a city, trees had to be cut down, and animals chased away. Then money came along, and things got even more complicated.
Once the Greek and Roman Empires had set the new benchmarks for Civilization (as reviewed in Civilization Monthly), they decided that everybody else was a barbarian (Greek for "all them dang foreigners").
Then places like the Middle East tried to point out how that didn't really make sense, and the Greeks and Romans laughed and said it didn't have to, because they were using it as an insult.
The word was actually derived from the idea that foreign languages were just gibberish and people who spoke them sounded like "bar-bar-bar..." all the time. In essence, they were lucky not to have been called the "Blahblahians" or the "Yattayattians".
China was going through almost the same thing, and came up with the own word for foreign nonsense-talkers. They were almost more racist about it though. They literally made a diagram showing "how civilized" the area around their capital was.
Empires continued to rise and fall at the hands of civilization, and finally a barbarian of far-reaching vision was born; Temujin of Mongolia. With a goal of uniting all barbarians and nomads on Earth, he tilted his head to the side, bugged his eyes out, and asked the whole planet "Suuup? Suuuuup?". Temujin's mom packed him a lunch, sharpened his weapons, and kissed him goodbye as he rode off to conquer the fucking planet.
Gathering an increasingly large army of warriors, soldiers, and complete psychopaths, his forces wrought terror and destruction wherever they went. The kind of cutscenes you see in "God of War" are probably less like real Greek wars, and more like Temujin's scorching wave of brutality. While Civilization had always had the upper hand before and had pounded the Barbarians into the dirt, it was not that easy to defeat Temujin's forces. Now known as Ghengis Khan, he had become a fearless leader and master strategist, and was seemingly unstoppable.
While the stereotype Mongolian raider is of a drunken sadistic rapist, such troops were not the majority, and have unfortunately tainted the public image of their entire army throughout history. Khan himself is not well-regarded in many places outside Mongolia.
Realistically, most of the troops were simply fierce fighters like those of any army from their time, and wanted perfectly normal things from the endeavor; land, gold, food supply lines, and recognition for their battle skills. Though many places were taken by force, plenty of their citizens willingly joined Khan's army, if only to be on the winning side.
It turns out that he offered a fair shot to everyone. Everyone. If they chose to join him, he would accept them and often give them a gift on the spot. This bizarre, blood-drenched Santa Claus routine is rarely mentioned, but it's exactly what he did. Once they were in his army, their rank would be limited by their own skill on the battlefield. Those who showed bravery, loyalty, or brains were promoted accordingly.
Despite all this rape business (which disgustingly was considered a perfectly valid weapon by many countries back then), Khan wasn't even a sexist. While far fewer women had a taste for battle, those who did were afforded with equal respect, and given the same rank as men who demonstrated their prowess.
With his sense of meritocracy, and his pure determination to conquer everything that did not willingly join him, Ghengis Khan was able to create the largest Empire history had ever seen, and no one has ever surpassed it. As unusual as it may be to think, through terror and violence, Khan came closer to uniting the people of the planet that anyone, ever.
Yeah, it's a little weird.
Between all the raping (and randomly fucking whatever foreign women willingly joined his army), he also managed to have a LOT of kids. In brief, his child support payments are widely regarded as the eventual collapse of his Empire. If only he had brought a few Trojans along, it probably would have gone better.