The Indo-European Hunter-Gatherer and Old European Neolithic Farmer dichotomy is personified in the concept of Apollonians and Dionysians.
Apollo is the god of the Sun, of rational thinking and order, logic, prudence and purity. Dionysus is the god of wine, dance, irrationality and chaos.
The Greeks found similarities between their Dionysus and the Hebrew Yahweh, and this belief was widespread enough that the Romans were printing coins in Judea with Bacchus, the Roman version of Dionysus. Note the “BACCHIVS IVDAEVS”
All of Rome's solar cults found themselves unified into Sol Invictus in the latter half of the 3rd Century AD. But even during the Julio-Claudian dynasty, the first few Emperors of Rome, did the Sun feature as a divine entity (as seen here on this Imperial bust from the 1st Century)
This last ditch effort of Indo-European Paganism, with its worship of the sky and the sun, to push against Dionysians failed. Sol Invictus became wholly irrelevant by the 5th Century AD.
Or did it? The Hebrews' Yahweh, with its similarities to Dionysus/Bacchus, is the most commonly worshiped God in the world today, but the Apollonians had the last laugh. They seized the leadership of those who followed the Son of Yahweh. They took this man, associated with wine and resurrection, and started depicting him a parhelion/Sun Dog/Sun Cross.
They changed his birth to the Winter Solstice, a date which measures the Earth's tilt away from the Sun. There are countless examples of Jesus in a sunlike position above the world.
Whether by intention or not, the Roman interpretation of Christianity mended the differences between the Apollonians and the Dionysians by creating a syncretic faith that resembles veneration of both while still asserting itself as something which is fully neither.
This isn't meant to be a Zeitgeist tier refutation of Christianity, either. Rather, I think this explains the broad appeal of Christianity across the Europe and the rest of the Roman Empire. It was hit both camps equally as hard.