Christmas Eve has, of course, long been thought of as a time of wakefulness and vigil. In Shakespeare's Hamlet, Marcellus reports the legend that prior to Christmas, the "bird of dawning singeth all night long," chasing away the fairies, witches and spirits that usually populate the nocturnal hours. The irrepressible "bird of dawning," in this context, is a figure for the stance of sustained prayerful anticipation that characterises a devoted Christian attitude to Christmas, a stance enacted in the celebration of Midnight Mass and in the All Night Vigils that are central to the Christmas liturgy in many traditions.
Contradictory expectations around sleep and wakefulness thus seem to attach themselves to Christmas Eve. It is a time for well-disciplined sleep, then, but also one for pious and open-eyed vigilance. No one should attempt to clap eyes on Santa, but no one should miss the opportunity to bear witness to the miracle of Christmas. These contradictions are memorably negotiated in one of the most successful Christmas songs of the modern era, John Frederick Coots and Haven Gillespie's "Santa Claus is Coming to Town," in which a demand for wakeful vigilance ("You better watch out") co-exists with a demand for good sleeping behaviour ("He sees you when you're sleeping/He knows when you're awake"). Santa Claus figures, in Coots and Gillespie's lyrics, as a kind of benign Sandman who appraises the sleeping behaviour of children, correlating it with their waking conduct ("He knows if you've been bad or good") and dispensing rewards accordingly. The sleep fantasized by this song is thus a sleep of faith or trust, a paradoxically vigilant sleep that banishes the sceptical gaze but keeps one (unopened) eye on Christmas morning.