I had forgotten how exhausting it is to live in Donald Trump’s world. He’s not only a political figure. He creates a psychological and social atmosphere that suffuses the whole culture — the airwaves, our conversations, our moods.

If there is one word to define Trump’s atmosphere, it is “pagan.” The pagan values of ancient Rome celebrated power, manliness, conquest, ego, fame, competitiveness and prowess, and it is those values that have always been at the core of Trump’s being — from his real estate grandiosity to his love of pro wrestling to his king-of-the-jungle version of American greatness.

The pagan ethos has always appealed to grandiose male narcissists because it gives them permission to grab whatever they want. This ethos encourages egotists to puff themselves up and boast in a way they find urgently satisfying; self-love is the only form of love they know.

The pagan culture is seductive because it lures you with images of heroism, might and glory. Think of Achilles slaughtering his enemies before the walls of Troy. For a certain sort of perpetual boy, what could be cooler than that? But there is little compassion in this worldview, no concept that humility might be a virtue. There is a callous tolerance of cruelty.

Tom Holland is a historian who wrote several fine books of classical history, like “Persian Fire.” Gradually he became more and more appalled by many of those ancient pagans — those Caesars who could slaughter innocent human beings by the hundreds of thousands while everyone thought this was totally fine.

“This is a really terrifyingly alien world, and the more you look at it, the more you realize that it is built on systematic exploitation,” Holland told the writer Justin Brierley. “In almost every way, this is a world that is unspeakably cruel to our way of thinking. And this worried me more and more.”