Why bash so big?

Maybe it was Seasonal Affective Disorder – depression triggered by a lack of sunlight – that made me a sick child every January.

Growing up in cold, grey English winters meant the end of Christmas lights left a massive black hole at the start of the year – and school came around in the first week!

Not so here. Australian summer holidays offer a buffer against harsh reality, granting the option to party through the season.

In fact, the medieval world did just that, celebrating Christmas right through to Candlemas, on February 2.

The date marked the presentation of Jesus in the Temple, and the end of Mary's confinement, 40 days after Christmas.

It also follows a more ancient tradition celebrating the return of the light, being halfway between solstice and equinox, a milepost on the journey from winter into spring.

In Australia that climatic trigger is missing as the heat goes on and on; but the underlying urge to keep the good times rolling seems hard-wired.

Some say the reason we traditionally wrap up Christmas on Twelfth Night – January 5 – is that biblical literalists wanted to focus attention on Epiphany, the legend of the Three Kings.

But Epiphany is just another version of Christmas, an event described differently in Luke and Matthew's Gospels.

Luke's nativity story of the shepherds and the stable is undated, but became associated with the Roman festival of Sol Invictus – the undefeated Sun - observed just after the solstice, December 21-22, when days became longer.

Celebrating Matthew's tale of the Wise Men or "Magi" 12 days later is a bit of a furphy since the text suggests the trio from the east arrived up to two years after the birth.

But celebrating Christmas 2015 in 2015, and Epiphany 2015 in 2017 would be too much of a Marty McFly-Doctor Who party trick.