Most of us have a picture of Jesus: Hollywood Jesus, left-wing Jesus, right-wing Jesus or whatever. One recent documentary claimed to have uncovered a secret gospel written from the perspective of Judas, the traditional betrayer of Jesus. Another tried to convince us that Jesus' tomb had been discovered, complete with evidence of his wife and family.

But what is so often lacking in these portraits is actual historical evidence.

So what kind of evidence should we expect?

The first thing to keep in mind is the sheer randomness of history. We have shopping dockets from lowly peasants and yet not one piece of correspondence from Emperor Tiberius, the man who ruled the world at the time of Jesus. Scholars have to draw their conclusions from the flotsam and jetsam that history throws up.

For example, the Gospel of John refers to a public bath in the Siloam district of Jerusalem " Jesus was meant to have performed a healing there. But archaeological digs throughout the city failed to discover such a pool. Some began to doubt the pool ever existed. Then, in June 2004 during sewerage repairs in Old Jerusalem, workers accidentally uncovered a huge public bath, dated to the time of Jesus. It is without doubt the missing pool of Siloam. Overly sceptical writers were suddenly a little embarrassed. They had wrongly supposed that the uncorroborated pool never existed.

The careful historian tries not to guess about the sort of evidence we should have for a figure like Jesus. Instead, they sift through the evidence that has survived and see what comes up.

So, what has come up?

Greco-Roman writers like Mara bar Serapion describe Jesus as a king, teacher and martyr. Historian Tacitus confirms that Jesus was executed by order of the Roman Governor Pontius Pilate. Toward the end of the first century, Josephus wrote up a history of the Jewish people in which he describes Jesus as a renowned wonder-worker and martyr, and he tells us that some were even calling him "Christ' or Messiah.

It's partly because of these non-Christian references to Jesus that no professional historian doubts that a teacher and reputed healer named Jesus really did live and was crucified early in first-century Palestine.

But this isn't where historians leave the matter. The most important sources for Jesus are those left by his followers " the writings now found in the New Testament.

The historian's goal is not to discover a source without an agenda " that would leave us nothing. The goal is to analyse every source in light of its point of view. This is how scholars read every ancient text, including the Gospels. Whether or not God was involved in the events surrounding Jesus is a personal, philosophical reflection. What the historian says is that the Gospels provide a unique window into one of the most influential lives ever lived.

1. Jesus the radical teacher

Most people know Jesus was a "teacher'. Some of his sayings have become proverbial: "Love thy neighbour', "The blind leading the blind', "The salt of the earth'.

But it would be misleading to think of Jesus simply as a wandering philosopher handing out pearls of wisdom. Most of what he said was far more confronting.

Scholars agree that central to Jesus' message was the "kingdom of God'. Luke records him saying, "I must proclaim the good news of the kingdom" that is why I was sent." The "kingdom of God' was a very Jewish idea. The Essenes, the guardians of the Dead Sea Scrolls, were especially interested in the kingdom. So much so that they removed themselves from Jerusalem and set up an alternative community in the desert of Qumran. They believed the holy city had become corrupt and they fully expected it to be judged when the kingdom came. The kingdom of God was intimately connected with the arrival of the Messiah " the king in this kingdom. He would sweep away the oppressors " the Romans " and establish a new order of justice and peace.

Things reached their climax a generation after Jesus. In the year 66, war broke out"”with devastating consequences. One by one, Jewish towns surrendered or were crushed. At Gamla, the residents must have thought they could beat the Romans. They started minting coins heralding a new era for God's people " the inscription read: "For the redemption of Jerusalem". But like Jerusalem a few years later, valiant Gamla was overcome. The Roman forces breached the wall, took possession of the city and crushed the trouble-makers. Any hope for a victorious kingdom was dashed.

But Jesus saw things very differently.

For Jesus, the kingdom would not come in a tornado of judgement on the ungodly. It would start small " almost unnoticed. On one occasion he spoke of a mustard seed " one of the smallest known at the time " and said, "This is what the kingdom of God is like'. The kingdom of God, in other words, would arrive in a way that was not entirely expected.

Perhaps the most shocking part of Jesus' teaching about the kingdom was his insistence its citizens were to be marked by love " even the love of enemies. Jesus wasn't the first to speak about love " it had a long tradition going back to the Jewish Scriptures.

But he did intensify the idea and apply it in quite a radical way. There was a brief war in Lebanon recently between Israel and Hezbollah. Imagine asking both sides to turn the other cheek and love each other. For Jesus, love meant doing good to those who would conquer you.

It was a radical call, and is just as radical today. It's no wonder things didn't go so well for Jesus.

2. Jesus the healer

Jesus didn't just teach about the kingdom of God. According to all of our sources, including ones written by non-Christians, Jesus demonstrated the kingdom in what theologians call "miracles'.
The reports of Jesus' healing miracles might seem the stuff of legend not historical reporting. Yet, numerous first-century sources, written independently of each other, all say the same thing: Jesus astonished people with healings. Even the first-century Jewish historian, Josephus, says that Jesus performed "baffling deeds'. It's his non-committal way of saying that Jesus did things no one could explain.

Historical evidence can only tell us what Jesus' contemporaries reported about him. And the evidence is clear that Jesus enjoyed a reputation as a healer. Even scholars today who reject the possibility of miracles all agree that Jesus did things friend and foe alike believed to be miraculous.

And there's something else historians are confident about: the meaning Jesus attached to his miracles.

Gerasa was the scene of one of Jesus' most famous " and bizarre " miracles. Jesus is said to have healed a crazed, demon-possessed man here by casting the evil spirit into a herd of pigs which rushed headlong into the lake and drowned. It was during one such exorcism that some began to suggest that Jesus' power was not from God but from the dark side.

Jesus' reply tells us what he thought his actions meant. For Jesus, his healings were not sorcery, trickery or even proofs of power. They were signs that the kingdom of God had arrived. According to the Old Testament, God's kingdom would overthrow evil and restore health and harmony to the world. That's what Jesus thought was going on when he cast out evil spirits and restored sick bodies.

As strange as it sounds today, Jesus was offering a preview of the time when God puts everything right in this world. The tiny "mustard seed' Jesus planted somehow inspired people to love amidst the violence and hatred of the world and to hope that God would one day make everything right. It's in this sense that the mustard seed would become the kingdom of God.

3. Crucified Jesus

Christian and non-Christian texts agree that Jesus died on a Roman cross.

On one level, what happened to Jesus was not extraordinary"”many people met a similar fate. In AD 70, during the siege of Jerusalem, the Romans crucified 500 Jews a day, until, according to Josephus, there was "no more space for crosses, nor crosses for bodies".

But when you consider the meaning Jesus attached to his cross, there's a sense in which his was a most extraordinary death.

So why was Jesus crucified?

The details are debated but the majority of scholars today accept that the Passion narratives of the Gospels are historically sound. They agree the trigger for Jesus' arrest and execution were the events of his final week when he came to Jerusalem for the Passover festival.

It began as Jesus entered Jerusalem with crowds shouting: "Blessed be the king who comes in the name of the Lord!" This was the moment he finally went public with the suggestion that he was some kind of king. It must have been spine-tingling stuff. But for those in power, it was alarming.

Yet, it was Jesus' protest against the Temple, that really lit the fuse. In the middle of the sacred precinct, he created a dazzling disturbance. Every Passover, as thousands flocked to Jerusalem, the priests would allow a livestock "super-market' to set up in the Temple forecourts so people could buy their sacrifices for the festival. It was potentially very lucrative. Jesus was outraged. All four Gospels record him driving out those who were buying and selling, and throwing over the tables of the bankers. Some experts believe Jesus was signalling God's overthrow of the Temple itself.

Then during the Passover festival of AD 30, Jesus sat down for his Last Supper. His words indicated not only that he would die but why.

Any mention of "outpoured blood' at this time would have reminded Jews of the Passover sacrifice. Passover recalled the Israelites' deliverance from slavery in Egypt centuries earlier. On that occasion their ancestors had daubed the doorposts of their homes with the blood of a lamb to protect them. In Jesus' day the male representative of the household would bring a memorial lamb to the Jerusalem Temple on the 14th day of the month of Nisan. After presenting it to one of the thousands of priests on duty, the worshipper killed the animal while the priest caught the blood in a sacred bowl.
The Passover lamb was far more than a memorial; it was a sacrifice. Its blood literally poured out before God. As families later gathered in their homes to eat the lamb they were reminded that God's mercy was theirs because his judgment had passed over.

Understanding all this clarifies Jesus' strange words at the Last Supper. By referring to his coming death as blood "poured out for others', he was suggesting that his personal sacrifice would save people from divine judgment. He was a kind of new Passover lamb.

The idea that God would require a blood sacrifice is a disturbing one for many Westerners. But it wasn't for an ancient Jew like Jesus. The God of Israel was perfectly just. He loved his people, but he couldn't simply forgive them. Just as a judge wouldn't release a criminal simply because he was positively inclined toward him, so God will not forgive the guilty without exacting payment.

So Jesus literally embodied this thought: his death would satisfy God's justice and so open up an avenue for God's mercy.

4. Risen Jesus

Back in the year 30, Rabbi Hillel or Shammai were better known teachers than Yeshua of Nazareth. But today Hillel and Shammai are virtually unknown while Jesus is honoured by millions. Why?
The answer is the missionary zeal of the first Christians, fired by the extraordinary claim that Jesus had been raised from the dead.

Yet what can historians say about a resurrection story?

Hundreds of scholarly books and articles have been devoted to the historical analysis of the resurrection. Scholars agree that there is an irreducible historical core to the resurrection story that can't be explained away as pious legend or wholesale deceit. Professor Ed Sanders, who warms a seat at the sceptical end of mainstream scholarship, puts it well: "That Jesus' followers (and later Paul) had resurrection experiences is, in my judgement, a fact. What the reality was that gave rise to the experiences I do not know."

The Garden Tomb is a popular site for pilgrims wanting to see where Jesus may have been buried. What motivates a person to visit a place like this is personal conviction based on a range of things. Evidence will play a part but so will deep questions like: Is there a God? Would God raise someone from the dead?

Historians ask much simpler questions: How early is our evidence for the claims about Jesus' resurrection? Most experts accept that Jesus' tomb was empty within days of his burial. It is mentioned in several independent sources but, importantly, we also know of a rumour started shortly afterwards that the disciples had stolen the body of Jesus. This tells us that even the first critics conceded there was an empty tomb.

But an empty tomb could be explained in a number of ways. What inspired the early Christians to believe that Jesus really was alive again was not an empty tomb but the claims of his disciples that they had seen him with their own eyes.

Many passages in the New Testament speak of witnesses to Jesus' resurrection. But one grabs the historian's attention above all others. Tucked away in one of the apostle Paul's letters is a quotation from a creed which scholars can date to within just a few years of the reported events themselves: The very early date of this summary rules out the suggestion that the resurrection story was part of a slowly developing legend.

It is an unavoidable fact of history that people claimed to have seen the risen Jesus from the very beginning.

5. What happened next?

The first Christians went out into the world, not as journalists with an unusual event to report, but as ambassadors with a message about God's mercy, what Luke describes as "repentance for the forgiveness of sins."

Megiddo is the site of the earliest Christian church yet found. One of the inscriptions refers to "the God Jesus Christ" and the early Christian symbol of a fish appears on the beautiful mosaic floor.
The Greek word for fish, ichthus, is an anagram of the words Iesous Christos Theou Yios Soter: Jesus Christ, Son of God, Saviour. Contained in this symbol is the message of historic Christianity: the status of Jesus as the "Christ' or Messiah, and his mission as the Saviour, the one who died for the forgiveness of the others.

There is, however, a condition, said the early followers of Jesus. God's mercy was not automatic simply because the Messiah had died and risen to life. It came only to those who experienced what Jesus called "repentance'. In the Gospels the word "repentance' is the Greek meta-noia. It literally means "changed mind".

This takes us to the heart of what Jesus expected of his hearers. People were to change their minds, about God, themselves and, of course, about Jesus himself. The point is worth stressing because so often in the history of Christianity, Jesus' demand for "changed mind' has been heard as a call just to improve one's behaviour " to be nice, honest, pure and so on. But changed behaviour was not the core of Jesus' message " despite the fact that this has sometimes been the obsession of the church.

The Jesus of history wanted more from his hearers than improved morality. He wanted a revolution deep inside the minds and hearts of men and women. This meant accepting his analysis that we each deserve judgment for not loving God with all our heart and our neighbour as ourselves. And it also meant trusting God's mercy and accepting his path of love.

All of this and more is captured in the words "repentance for the forgiveness of sins".

And it's because of this that the life of the historical Jesus continues to intrigue and inspire millions of lives even today.