jan 1, 1000000000 BC - Prime Celestial Arishem brings light into the Universe

Description:

From the opening scroll of Eternals; "Before the 6 singularities and the dawn of creation (the big bang), came the Celestials. Arishem, the prime celestial, created the first sun and brought light into the Universe"
From Guardians we know that the 6 singularities have existed "before creation itself" and have thus always existed infinitely. It was only during the big bang 13.8 billion years ago that those singularities were forged into physical stones and scattered across the universe.
So the Celestials were around before the big bang and before the infinity stones, but it doesn't make sense to say they were around before the 6 singularities themselves since they don't have an origin point.
Either way, both the stones and the celestials have existed far beyond the limits of this timeline, so for these purposes they can only be represented as occurring at the same time.

Added to timeline:

Date: