You might have heard the story about the German friar who nailed 95 provocative statements to a church door a long time ago, triggering something we now call the Reformation.

If you’re looking for a modern interpretation, 500 years ago next Tuesday, Martin Luther posted a particularly incendiary series of tweets. He wanted to provoke debate about corruption in the Roman Catholic Church. He certainly achieved that.

Sadly, Luther couldn’t take advantage of Twitter — and it’s generally accepted that he didn’t actually hammer his arguments to a church door. Instead he used the then cutting-edge technology of printing. But the impact was no less dramatic. What Luther wrote went around Europe incredibly quickly; it was the viral content of its day.

Within two decades Europe was split between Protestants and Catholics in a process called the Reformation. The conflict that generated (which began in England in the early 1530s) continued for hundreds of years. The first century or so was especially bloody and violent.

That is why I wanted to share the story of two Cardinal Archbishops (the most senior members of the Roman Catholic Church) — one a predecessor, the other a friend. On this anniversary they show how much there is to mourn but also how much to celebrate.

The first is Cardinal Pole, who was Archbishop of Canterbury in the mid- 16th century. In 1556 he planted a fig tree in the grounds of Lambeth Palace, where archbishops have lived for 800 years. Rumour has it that he planted it to celebrate trying his predecessor for heresy, and then having him burnt at the stake. The tree is still there today.

Fast-forward five centuries and you come to another Cardinal Archbishop — the Archbishop of Westminster, Cardinal Vincent Nichols. Recently I was at a service with him in the Roman Catholic Westminster Cathedral. It was a communion service, one of the most solemn services in the Christian Church globally. Because of the events of the Reformation and the history since, it remains impossible for Anglicans and Roman Catholics to receive communion together.

At that solemn moment in the service I lined up at the front with everyone else. But because I could not put my hands out for the bread and wine, I knelt down to be prayed for by Cardinal Nichols. He took my hand and lifted me to my feet. Both of us had tears in our eyes. We are the closest of friends, and being reminded of the divisions in the global Church pains us both very deeply.

But even if you have never had anything to do with the Christian faith, those statements from Luther that started to go viral in 1517 have shaped your life — from the books you read, to the job you do, to the political system you take part in.

We have plenty to be grateful for — particularly the way that the Reformation developed our language and communication technologies. The Reformation also paved the way for how faith is now conventionally a personal choice, rather than something imposed by our society. We may take that for granted today but it’s a trend whose roots are found in the tumultuous events of 500 years ago.

The arts, sciences and literature flourished, thanks to the Bible becoming available in each person’s language Justin Welby

It opened the way to the development of much stronger ideas of the nation state — especially the different kingdoms and principalities of what is now known as the United Kingdom, and eventually the development of British identity.

The arts, sciences and literature flourished, thanks to the Bible becoming available in each person’s language, rather than only in Latin. People began to own books, starting with bibles and prayer books.

Economically, there were creative and innovative developments — especially in finance and banking. It became acceptable to charge interest on loans, which led to the sort of economic development that had not been possible before. If you’re reading this on your way home from the City or Canary Wharf, your work is partly down to that German friar.

But as the story of the two cardinals shows, there was also much to mourn, and much for which to be sorry. Entirely against the teaching of Jesus Christ, Christians learnt to hate and kill each other, even more than they had done in the past. They sought to impose faith through force when it should be a personal choice (although the Reformation eventually led to a breakdown in that coercion, it took a long time to do so).

At the heart of the Reformation was something Luther had seen as he read the Bible. He saw that God offers forgiveness of sins, and the promise of heaven, not because we do good works but because we trust in God. There’s an old hymn that says: “Nothing in my hand I bring,/Simply to your cross I cling.”

That was Luther’s immense discovery: the grace and love of God for human beings in all their failings and faults.

Tragically, those failings and faults showed themselves in the working out of the Reformation. In this year of its 500th anniversary, as my friendship with Cardinal Nichols shows, we have learned once again to love one another — and to seek to bless and love the world in which we live.