Weren't their gods the sun, and seasons.

There wasn't one god until an emperor declared the other god's false. It was only to be their god. Then the mortals killed him. Because he wasn't god. They decided it was best to appoint god's messenger. So he could tax them for it.

As far as that event, there are a few natural and celestial events which can cause this. Volcanoes, and planetary impact.

Weren't their gods the sun, and seasons.

There wasn't one god until an emperor declared the other god's false. It was only to be their god. Then the mortals killed him. Because he wasn't god. Because they decided it was best to appoint god's messenger. So he could tax them for it.

As far as that event, there are a few natural and celestial events which can cause this. Volcanoes, and planetary impact.