A belly full of ale, a snog under the mistletoe and a heap of presents. Has Christmas lost its meaning? In fact some things don't change.

Every year at Christmas it's traditional to bring in armfuls of greenery into the home.

Fir trees are put in a bucket and sprinkled with baubles, holly and ivy are wedged into mantelpieces and picture frames and mistletoe is hung over doorways.

Bringing the forest into the home - like many of Christmas traditions - has its roots in pre-Christian days when we all worshipped many gods.

Festivals were held around the winter solstice, the shortest day of the year, to welcome back the longer, lighter days and pay tribute to the sun.

And evergreens such as holly, mistletoe, ivy, and certain trees became a symbol of eternal life and renewal.

Ancient Egyptians are believed to have brought greenery into their homes during winter festivals.

The ancient Romans certainly decorated their temples and homes with greenery and flowers for their winter festival - called the Saturnalia - famed for its sexual depravity.

And the Druids gathered mistletoe and hung it in their homes because they believed it had miraculous powers.

Dr Brian Bates, senior lecturer in psychology and director of the shaman research programme at Sussex University, said: "In the early tribal cultures of Europe there were huge midwinter parties, involving an entire tribal group, with a shaman taking centre stage wearing a crown of holly and ivy, representing the eternal life of 'evergreen' nature."

The Romans thought mistletoe brought peace and when enemies met under it they threw down their weapons - we get our custom of kissing under the mistletoe from this tradition.

Even carol singing had its precursors in shamanic festivals.

Dr Bates said: "Carols were originally magical incantations, intended to induce ecstatic states of mind during which the spirit of Father Christmas made his appearance."

Ah yes, Father Christmas. According to Dr Bates, there's much more to him than the jolly old fellow that hands out presents in department stores.

He is thought to be linked to the god Woden, worshipped by the Anglo-Saxons and Celts.

At midwinter Woden, the god of magic and healing who rode across the sky on an eight-legged white horse, came to Earth in the form of Father Christmas, dispensing goodwill, luck, peace, oh yes and presents.

Hallucinogenic plants

Dr Bates said: "Gargantuan ale drinking fuelled the parties and helped the spirit of Woden Father Christmas to enter the revellers.

"The shaman who was to become Father Christmas became ecstatic, laughing as does our modern version of him, with the extra help of hallucinogenic plants.

"He imagined himself flying to mystic destinations, just as we portray Father Christmas today."

As Christianity spread, many of these traditions were adapted to give them a Christian meaning.

Christians believed Jesus Christ to be the light of the world they chose the time of the pagan festivals and the return of sunlight to celebrate his birth.

Father Christmas was given the name St Nicholas after a bishop in the ancient Turkish town of Myra.

And the eight-legged horse was put out to pasture and replaced by a sledge pulled by reindeer.

There was a short blip in the 17th century when the Puritans abolished traditional celebrations. Throw a party and you get arrested.

But it was revived by the Victorians who, contrary to myth, enjoyed a good knees-up.

Dr Bates said: "Many people today believe the traditional 'Dickensian' Christmas started in Victorian times.

"In fact, the traditional Christmas restarted in Victorian times, reviving many of the old customs which had been stamped out during the Puritans' purge."

The Victorians also popularised the Christmas tree.

An illuminated conifer was a German idea, but it caught on after 1840 when Queen Victoria and her German husband, Prince Albert, were pictured at Windsor Castle with their Prussian tree.

But what will we be able to offer the Christmas revellers of the future?

A big crush at the supermarket checkout and repeats of Only Fools and Horses?