Christian civilisation has two components: Christianity and civilisation. The latter came first. In European mythology, Prometheus imparted civilising arts, thus initiating civilisation which means cities, including Troy and its successor, Rome. Prometheus, a pre-Olympian deity, was at the beginning of his mythological tradition whereas Christ is presented as the culmination of the Biblical tradition that had started with creation. The Promethean tradition includes the Trojan Aeneas, the Roman founder Romulus and the Roman Caesar. The Judeo-Christian tradition includes the forefather Abraham, the founder Moses and King David. Both progress from myth to history.
The Fourth Evangelist started to synthesise the two traditions when he ret-conned the Greek Word into the Biblical creation. "In the beginning..." (Gen 1.1; Jn 1.1). However, it was the Roman Emperor Constantine who Christianised civilisation. Under Constantine, Christ replaced Jupiter/Zeus, who had imprisoned Prometheus for civilising mankind, as the god of the state. Notionally, the present writer still inhabits Christian civilisation. Christianity remains the British state religion under Elizabeth II as it had started to become the Roman state religion under Constantine I. In fact, I was indoctrinated not in the Church of England but in the form of Christianity that still recognises the Pontifex Maximus, the chief priest of the Roman state religion, a post that had been held by Julius Caesar.
Post-Christians can appreciate Classical and Christian mythology, art and literature and can remain Promethean.
See also Revising the Origin Story.