The pope is coming. Liberals, be glad

The pontiff's state visit marks the end of one of history's most murderous hatreds
Tintern Abbey
Tintern Abbey, which fell prey to Henry VIII's dissolution drive Photograph: The Photolibrary Wales / Alamy/Alamy

The face of a medieval monk looks out of a glass case in the British Museum in London. His young, handsome, tonsured head was exquisitely carved in stone. It is life-size. You can see where it has been broken from the wall, for this compelling, realistic portrait was once part of the architecture of a British abbey. All around it in the museum's medieval gallery are other fragments from religious buildings that were destroyed after Henry VIII dissolved the monasteries in the 1530s.

In the V&A too you can see stained glass from lost abbeys, treasure from desolated religious houses. All around Britain you can find deliberately ruined monastic buildings, picturesque now.

It would be inaccurate to call the monk in the British Museum a "Catholic" because Catholicism in its modern form is as much a product of the Reformation as the Protestant Church of England is. As Christendom divided in the 16th century, practices that had grown up informally over a millennium were scrutinised, analysed, and either rejected or – if you remained a follower of the pope – defended. Those tenets of the Old Religion that seemed to work for a newly embattled church were codified by the Council of Trent and then promoted by Catholic artists. Meanwhile, in Britain, radical Protestants were deeply suspicious of visual images in church. They smashed "idols", defaced statues, demolished stained glass, ravaged rood screens.

Religion became a topic of dispute in 16th-century Europe, as it is today. People reached new heights of intolerance in pushing their points of view in deliberate deafness to the other side – as they do today. Let's not sentimentalise medieval Christianity; it had a very long history of persecuting heretics such as the Cathars, not to mention Jews. But in Britain after the Reformation those who defined themselves as what we call Catholics became a truly persecuted minority. It was not only stone monks that were destroyed. Real monks and nuns were burned.

If you contemplate the history of art you can hardly avoid this violent legacy of religious bitterness. Atheist critics of the pope's visit to Britain will, of course, argue that it just proves the madness and cruelty of all religion. Sure, in the abstract, I agree. But in human reality, as a matter of lived experience, Catholics were a persecuted group in Britain for centuries. Even after burning at the stake went out of fashion they suffered a stringent set of social and political restrictions until religious minorities were emancipated in the 19th century. As for the visual glory of medieval art, it never returned. This is a history of persecution, and the first state visit by a pope since the Reformation is a liberal moment, for it marks the official end of one of the great divides of history, the disappearance of one of the most murderous hatreds. It is an event to be quietly glad about, if you believe in a tolerant secular society.