In the modern world the absence of sunlight no longer means complete darkness, but the short winter days and cold weather are eased by the festive lighting at Christmas which has its origins in the solar cults of the ancient world. The megalithic site at Newgrange is thought to have been an astronomical observatory for pinpointing the exact moment of the winter solstice, "the year's midnight", and the reversal of the dark season. Fire festivals were regular events throughout the year and were connected with the sun god, whose influence was at its weakest in December. Darkness bred fear and was the natural element of denizens of the underworld, witches and suchlike, who perpetrated all kinds of mischief in the world of men, from cattle diseases to the blighting of crops.

The early Christians in Egypt celebrated the Nativity on January 6th, but some time in the fourth century December 25th was adopted to coincide with the fire festivals of the pagan Mithraic cult, a serious competitor with the infant Christian religion. The fathers of the church had enough sense not to try to drive out the old religions but to assimilate them instead. Many Christian symbols – the cross, the trinity and the midwinter nativity festival – have their origins in the much older religions which they supplanted.

In later times the fire festival survived in the folk tradition of keeping a Yule log under the grate of the fire where it would glow throughout the season without burning away. The log was thought to have magical properties: in some parts of Europe the ashes were scattered on the crops to cleanse them of disease and to promote fertility. Elsewhere the log was kept in the house throughout the year to protect against all kinds of misfortune. Today the tradition survives in the practice of placing a candle in the window of the house. The midwinter festival was an indoor festival as opposed to the public bonfires of midsummer. Today's Christmas lights have as much to do with the commercialisation of the season as with the ancient superstitions to which they can be traced. However, at another level the Christmas lights have the same effect of lightening the dark season and prefiguring the return of the sun in the Springtime.