Good tidings of great joy

Another Christmas season looms. Millions of Australians will attend a token church service or two, and familiar carols will be belted out. But most people will give only cursory thought to the events – about 2,020 years ago – which gave rise to these traditions.

Is the whole thing pious fiction? Some would insist it is. Others would say that, whatever actually happened, it had no cosmic significance.

What cannot be disputed is that the religion now known as Christianity emerged in the Roman province of Judea (part of modern-day Israel) in the mid-first century AD. It was "started up" by a few hundred people who had been followers of the man Jesus of Nazareth. They claimed that Jesus was, literally, God "made flesh", and their grounds for that claim were recorded in the documents which became the New Testament. Billions find those grounds convincing.

How much of the Christmas story can confidently be accepted as fact, and how much must be taken on faith?

According to New Testament scholar G.N. Stanton, "the infancy narratives contain both history and poetry, as well as considerable literary and theological artistry, all of which are closely interwoven and cannot easily be disentangled".

Countless experts have tackled these issues and what follows is the tip of an iceberg. For those who wish to learn more, Raymond Brown's The Birth of the Messiah may be the most comprehensive work to date.

The Gospels, as ever, are the starting point. But herein lays a curious problem: only two of the four, Matthew and Luke, deal with Jesus' birth at any length. There is overlap between them on key points – which is significant, because the authors worked independently of each other – but there are also notable differences of emphasis.

Tradition has it that Matthew's main source was Joseph, Jesus' (human) father, and that Luke's was Mary, his mother.

With that in mind, it's convenient to scrutinise the Christmas story in two stages.

First, its main factual elements: these are either realities of history or not, assessable on the balance of probabilites by the usual methods. Second, the specifically supernatural elements of the story.

When was Jesus born?

Awkwardly, it was not in 1 AD – even though the term "first century" is popularly understood as connoting the one hundred year period immediately following Jesus' birth. (AD stands for Anno Domini (Latin for the year of our Lord) and BC for before Christ.)