You’ve raised fair questions. Yes, human societies have always had codes of fairness and cooperation. But what Tom Holland argues in ‘Dominion’ is that Christianity universalised those instincts in a way that was completely new. It wasn’t just “protect your own tribe” — it was “every human life matters,” even the poor, the outsider, even the enemy.
Holland gives the example of infant exposure in Rome. A baby wasn’t considered part of the family until the father formally accepted it. If he didn’t, the child could be abandoned — often girls or disabled infants — and this was accepted as custom, not considered murder. Christianity broke from that. From its earliest teachings, exposure was condemned, because every child was seen as bearing God’s image. As Holland points out, the belief that even the weakest life has equal worth was a revolutionary moral stance in the ancient world.
On slavery — yes, Christians owned slaves for centuries, but the logic of their faith carried the seeds of abolition. Once you accept that all souls are equal before God, the institution is undermined from within. That’s why abolitionist movements like Wilberforce’s were so deeply rooted in Christian conviction.
So while morality may evolve, Christianity introduced something genuinely new into the world: the belief in the intrinsic value of every human being.
And that shift reshaped the moral landscape in ways we still take for granted today — from law and social norms to the foundations of the welfare state and modern ideas of justice.
Because of this, what we consider justice — what we consider right and wrong — is rooted in Christian principles. Unlike the Romans or other ancient civilisations, where morality was based on custom, status, or family duty, Christianity framed justice around universal human worth.