The opening Canto of Savitri has been used by the Master poet as a symbol making it clear that the poem is not just the story of conjugal love but a cosmic poem that takes up the theme of the eternal Love between the Divine Mother and the human soul. So, while Sri Aurobindo is outwardly describing the Dawn of the day when Satyavan is destined to die, he is also hinting at the Dawn of a New Creation wherein darkness would end, conquered by the Light. Savitri is the Light that comes as Dawn bringing new hope for the soul of man that must pass through the portals of death again and again to recover its immortality. The beginning of creation is the moment when the soul plunged into the darkness of the Inconscience. This moment connects with the day being described which is the day of its redemption.
Affectionately
Alok da
Reference:
Savitri: Book 1 Canto 1 | Dr Alok Pandey
YT Link: https://youtu.be/hVxSqr84n20