Christmas is truly the winter festival of light

Some centuries later, Pope Gregory the Great instructed the first missionaries to the English to cleanse and reconsecrate pagan shrines and to adapt the pagan feast days as celebrations of the saints. In essence, this is an application of the belief that grace builds on nature, and that wherever goodness is found in any human culture it may be accepted as a glimpse of the goodness of God.
It also seems worthwhile to consider why it was this pagan feast day on December 25 was chosen as a celebration of the birth of Christ. Perhaps it lay in the Church’s recognition that the days after the winter solstice — when the darkness stops increasing and light starts coming back into our world — seemed like an ideal time to commemorate the birth.