The legend as I know it, the Oak King and the Holly King would battle. The Oak King won the battle signifying the return of the sun. As long as the Oak King reigns, there would be sun. Remember, the modern Wheel of the Year as we know it, is agriculturally based.
… there is no evidence of an ancient Wheel of the Year in its present form but it is clear that the Celts of thousands of years ago celebrated the festivals the wheel highlights, even if these celebrations were known by another name now long lost. In the ancient Celtic culture, as in many of the past, time was seen as cyclical. The seasons changed, people died, but nothing was ever finally lost because everything returned again – in one way or another – in a repeating natural cycle… Scholar Raven Grimassi writes: In essence, Yule symbolizes the renewing cycles of life, as well as rebirth, rejuvenation, and growth. In ancient Pagan times, the Winter Solstice was the time when people believed the new sun god of the year was born.