From Hesiod's poem to Nyx, the Greek personification of night:
"There also stands the gloomy house of Night;
ghastly clouds shroud it in darkness.
Before it Atlas stands erect and on his head
and unwearying arms firmly supports the broad sky,
where Night and Day cross a bronze threshold
and then come close and greet each other."
(Hesiod, Theogony, 744 ff. )