The Egyptian world
The Nile and its inundation were basic to the Egyptian world-view. Unlike most peoples, the Egyptians oriented towards the south, from which the river came, so that the west was on their right - with the result that it was the 'good' side for passage into the next world. The year and calendar were adjusted to the Nile and the stars. New Year was in mid July, when the river began to rise for the inundation; this coincided approximately with the reappearance of the star Sirius (Egyptian Sothis) in the sky after 70 days' invisibility. Sothis provided the astronomical anchor for the 365 day calendar. The river defined three seasons of four months: 'Inundation' and 'Emergence' (November-March) when the land reappeared and could be cultivated, and 'Heat' or Harvest, when crops were gathered and the water was lowest.
In some ways, the Nile's fundamental importance for the sustaining of human life may be more obvious to us than it was to the ancient Egyptians. They thought of its regular flooding, so essential for the fertility of the land it ran through, as the natural state of affairs - so much so that they termed rain in other countries an 'inundation in the sky'.
In order to appreciate the Nile's position in antiquity, we should see it through ancient eyes, remembering the ancient distinctions between the divine and the human. The Egyptians had a relatively matter-of-fact attitude towards the river, whose inundations could sometimes cause destruction but were seen a beneficent moral force. Egyptian gods, by contrast, were seen as complex beings whose abode was outside the physical world of the land and river. It was left to the Greeks and Romans to make a god of the Nile, as they had of the other rivers of the world.