EXCEPTING the sudden new values proclaimed after revolutions — the French revolution with its new calendar and Festival of the Supreme Being, the Russian with its “Octobering” ceremonies replacing Christenings — new ideas and new forms of life invariably continue in old shells. Just as the Pantheon became a Christian church, and Hagia Sophia switches from cathedral to mosque, we continue to use “Christmas” as a catch-all term for a combination of a millennia-old midwinter gathering and a hypercapitalist festival of consumption.

Yet what happens to the older shell as it is filled with new content? Is it affected, does it comment on its new surroundings?

During a visit to Nottingham, I had a drink in the Pitcher and Piano — or, as it was previously known, the High Pavement chapel. The church was opened in 1876 for the use of the United Presbyterians. The exterior shell of this building is interesting enough — a strong gothic presence surrounded by former lace mills and warehouses. Walk inside, though, and the change slaps you in the face.

For shock value, it’s best experienced on a Saturday night. The breathtaking heights of the church’s narrow, neo-gothic vaults now look down on a typical chain-pub arrangement of nooks, booths and tables. But what strikes you especially are the preserved stained glass windows, of captivating delicacy and elegance. The main seven-part window is filled with personifications of various virtues (labour, theology, philanthropy, etc). Other windows include haunting war memorials — soldiers among ruins — alongside biblical scenes.

How does this manage to exist alongside the building’s current function? Well, the 1998 redesign provides a series of stairs and walkways so that the serious drinker can inspect the stained glass. The building and its artworks are treated with the most scrupulous respect.

St Catherine’s Church, Krakow, which I also visited this year, is a 14th-century gothic church. Its high vaults give the church very good acoustics — and this, presumably, is why it was hired by the Unsound Festival, an annual experimental music fest. This year, the festival’s theme was “The End”.

Playing were American singer-composer Julia Holter, and American electronic musicians Tim Hecker and Daniel Lopatin. The naves were crowded with people who most likely hadn’t been in a church since their teens. Both Holter and Lopatin-Hecker made an effort to sound “devotional”, although there were no overt religious references.

In both cases, something religious was secularised and commemorated; people who don’t believe thought they were being respectful towards the imagery of belief. This then eventually spills over into comedy, when you have pub walkways installed for you to look at stained glass, or when you find electronic musicians trying to summon the horsemen of the apocalypse with their laptops. The pretence is that we’re not destroying the old, but continuing it — perhaps, even, that we’re not doing something new at all. The approach of the French or Russian revolutionaries, who declared new festivals and rituals for new values and a new society, had the virtue of greater honesty. — The Guardian, London