They always come together.

Their duality represents, then, not successive stages but one stage in day's approach, when light is dark and dark is light.

In comparing the Acvins to other pairs[111] this dual nature is frequently referred to; but no less is there a triality in connection with them which often in describing them has been ignored.

This is that threefold light which opens day; and, as in many cases they join with Dawn, so their color is inseparable.

Strictly speaking, the break of red is the dawn and the white and yellow lights precede this[112].
Thus in V.73.