Arguably, today we live in the most liberal time in human history. Most people believe in the basic human rights and sacrifice a portion of their freedoms for their respective democracies to protect those rights and freedoms. If today we live in a liberal world, then that most mean that our ancestors must have lived in a less liberal world; a realist world. Realists, who cared only about their survival in a total-sum world, are and is the backbone ideology of past empires. In their minds, if you don’t expand and build upon your empire, it will fall and crumble to the ground, and they weren’t necessarily wrong either. History has their side, eventually the Egyptians fell, as did the Assyrians, Romans, etc. Thus, empires grew and grew, assimilating more and more people under common beliefs.
It’s under these empires that allowed for unified currency and the spread of religions. In a way, people would have wanted to be under the rule of an empire, it allowed them more opportunities because of the singular currency. The establishment of agreed-upon trade allowed for widespread cooperation, as well as a boost for the empire, giving it more incentive to expand its horizons and assimilate more and more people.
As a side-effect, more and more travel led to the spreading and sharing of ideas and beliefs, particularly religions. Yes, originally the Roman empire had banned Christianity as they saw it as a threat to the throne, but that didn’t stop Christians from hosting secret meetings and dying at the mouths of lions (pretty badass if you ask me). Eventually, the Romans subscribed to the “if you can’t beat them, join them” idea, and allowed for Christianity, and Constantine himself told his people of his “vision from God.” What once was a threat to the throne was now one of its most powerful assets. Simply put, if you were to go against the empire, it would like to go against God himself, and you don’t want to do that, do you?
These three bring the dawn of a new world or did at least. In Harari’s words, the unification of humankind was brought on by commonality and the belief of the norm. “We are put of the Roman empire because we believe in God and our parents and their parents were Roman too.” If we do not learn history, we would not know that if we kept going back on that family tree, at some point, you’d come to an ancestor that was a Carthaginian. Not studying history keeps our horizons narrow; we’ll stay as Romans because that’s all we’ve ever known. Studying history “ables us to realize that there is nothing natural or inevitable about” the Romans, “and that the world might well be arranged differently.”