The sun had now risen clear of the eastern hills. Its cool light travelled quickly down the western slope of the col until the wide plain came into full view.
What does “until the wide plain came into full view”?
Does it mean “until the wide plain was lighted completely”?
Probably yes, in the sense that the wide plain became fully visible to the narrator (or other observer). However, I don’t think it is tremendously clearly described. It reads somewhat as if the plain came into the view of the sunlight, which is an odd idea.