Both day and night, on the fourth and fifth days of the week, we made a determined attack on the city from all sides. However, before we made this assault on the city, the bishops and priests persuaded all, by exhorting and preaching, to honour the Lord by marching around Jerusalem in a great procession, and to prepare for battle by prayer, fasting, and almsgiving. Early on the sixth day of the week we again attacked the city on all sides, but as the assault was unsuccessful, we were all astounded and fearful. However, when the hour approached on which our Lord Jesus Christ deigned to suffer on the Cross for us, our knights began to fight bravely in one of the towers … One of our knights … clambered up the wall of the city … Our men followed, killing and slaying even to the Temple of Solomon, where the slaughter was so great that our men waded in blood up to their ankles.

Another author wrote: “neither women nor children were spared.”

This is, sadly, not an isolated incident. The Emperor Constantine painted crosses on the shields of his soldiers. Need we mention the atrocities of the Conquistadors in South America, the terrors of the Inquisition, or the witch hunts of Salem, or the Puritan Oliver Cromwell using the Bible to justify genocide against Catholics in Ireland.

Just last year, I visited the spot in Zurich from which a group of Anabaptists were drowned in the river under one of my theological heroes, Ulrich Zwingli, for their heretical views.

Closer to our own time, Catholics and Protestants have only recently emerged from a decades-long violent struggle in Northern Ireland.

As theologian Miroslav Volf has written: “Beginning at least with Constantine’s conversion, the followers of the Crucified have perpetrated gruesome acts of violence under the sign of the cross.”

So, it seems like an open and shut case. Christians and their churches have endorsed unjust and excessive violence – and not just incidentally but in the name of their faith.

Perhaps the hymn we should all sing is John Lennon’s Imagine:

Imagine no religion, it’s easy if you try …

Imagine all the people, living life in peace …

Surely there is something poisonous about Christianity? The Nobel prize-winning physicist Steven Weinberg puts the case this way: “With or without religion, you would have good people doing good things, and evil people doing evil things. But for good people to do evil things, that takes religion.”

You’ve heard your Uncle Barry or Joanne at the next desk say the same thing: “religion causes wars.”

So, here’s a question for us: is there something inherent in Christianity that not only fails to prevent violence but makes it much, much worse?

So, here’s a question for us: is there something inherent in Christianity that not only fails to prevent violence but makes it much, much worse?

Some writers, such as the atheist Sam Harris, have argued that monotheism is the problem. Belief in one God only has many advantages over polytheism. But monotheists can’t accept that their god is one god amongst many. If you believe that your god is the creator of heaven and earth, and is the only true god, then you are making an exclusive claim about your god over and against other gods. Monotheism brooks no competitors. It is not tolerant or accommodating. It names as the first sin false worship – worship of gods that are not god, and it says that from this sin come all others.

And Harris and others have argued that this idea, common to Judaism, Islam and Christianity, leads to their violent tendencies. The desire to protect the oneness of God leads to the exclusion, by violent means if necessary, of all that is felt to corrupt it. War can become a religious duty – a holy war, in other words. Jihad, or crusade. Whatever nice and peaceful teachings may be found in religious books, they are obscured by this fanatical desire to protect the oneness of God.

Add to this the idea of bloody sacrifice at the heart of Christianity and you have a dangerous recipe. The cross is an ever-present reminder to Christians, say the detractors, of both the bloodthirstiness of their God and the fact that the world is out to get Christians. If God uses violence, then surely it is justified for human beings to use it in his name.

And the blood flows, as a result.

So, what to say in response to these charges?

While it is impossible to deny the fact that Christians have at times endorsed and carried out appalling acts of violence in the name of the crucified Christ, it is simply not the case that there is something inherent in Christianity that makes it so.

I want to make three points.

First, Christianity has been co-opted for violence by those interested in power. But take away the Christianity, and you still find empires, nations, and political factions sponsoring violence.

The first emperor to become a Christian, Constantine, did so because he won a military victory after he painted a Christian sign on the shields of his soldiers. So he made Christianity the official religion of the empire.

We still have officially Christian nations down to this day – the United Kingdom, Denmark, Greece and Argentina, to name just four.

Now, while on the one hand much good can come from the church influencing a state, it is also the case that a state will try to co-opt Christianity for its own ends – to justify its own often violent actions.

Religion, including Christianity, has been associated with war and violence. But it is far too simplistic to say that Christianity causes wars.

If there is one common factor in human conflict, it is not religion but national or tribal identity. The supposedly peaceful secular liberal democracies of the past 200 years have been no less bloodthirsty than religious regimes, and avowedly atheistic governments have been much worse.

First, Christianity has been co-opted for violence by those interested in power. But take away the Christianity, and you still find empires, nations, and political factions sponsoring violence.

The classic case for Christianity as warmonger that is often cited is the Thirty Years War that tore Europe apart in 1618-48. That terrible war, pitting Protestant against Catholic, led to the birth of the idea of the secular state.

So the story goes. But the reality is far more complex. These wars of religion were often fought between alliances of Protestants and Catholics on both sides. What was really going on was not a war for religious supremacy but for national identity.

Secondly, Christianity does make universal claims, but it makes them in the name of love and peace. The excessive violence that mars some phases of Christian history is at odds with Christianity itself. There is no endorsement of the idea of holy war in the Christian Bible. The wars of conquest of the Old Testament are not seen in the New Testament as a pattern for Christian expansion. In fact, the opposite.

Jesus was a king, and was proclaimed as Lord, but he was a king like no other. In John 6:15, we read that the people wanted to make him king “by force” – they’d just seen the feeding of the five thousand. What was Jesus’ response? It was to withdraw to a mountain. When Peter drew a sword to defend Jesus in the Garden of Gethsemane, Jesus rebuked him.

Recently the Chinese President Xi Jinping said, according to the Wall Street Journal:

“In the West you have the notion that if somebody hits you on the left cheek, you turn the other cheek. In our culture we punch back.”

Now I’m not sure that Jesus’ teaching has really affected our culture as much as he thinks. But even the President of Communist China knows that the central figure in Christianity taught against violent retaliation.

Christianity does make a universal claim. It is for everybody, regardless of race, or gender, or status. Christ is proclaimed as Lord of all, not Lord of some. He’s not our personal Lord and saviour. All nations and peoples are called to know him. It’s a terrible distortion of Christianity to say that it’s an ethnic religion.

But clearly, Jesus and his followers only ever endorsed preaching the gospel accompanied by acts of sacrificial love even for our enemies as the means to Christian expansion.

Which leads me to my third point: if we are to recognise Jesus as one of history’s greatest teachers of peace, then we cannot pretend that his monotheism was incidental to his teaching.

Jesus was not some first-century hippie, just telling everyone to be kind to one another. Remember: he was Jewish to the bootstraps. Jesus believed in the one God who made heaven and earth, and who was the God of Abraham, Isaac and Jacob. For him, love of the one God and love of neighbour – even an enemy – were inextricably linked. You can’t pull one ingredient out: for Jesus, we love our neighbour because we love God, or rather because God loves us, and we learn it from him.

The gospel that the apostle Paul preached was a declaration of the supreme power of the risen Lord Jesus. But this ruler’s rule, according to Paul, was symbolised by his death as a victim of the emperor’s regime, out of love.

And Christians are likewise called to represent this one Lord, not by acts of violent oppression but by living lives that look like Jesus’ life and by speaking his name.

It is a tragedy that we haven’t always done so. Christians certainly have endorsed acts of horrendous violence. But when they have done so – even when Popes and bishops and preachers have done so – they have misrepresented the Lord they claim to serve.

Michael Jensen is the rector of St Mark’s Anglican Church in Darling Point, Sydney, and the author of several books.