Where am I? I am sitting in a dark rumbustious coffee shop that used to be an ironmongery, young persons over their computers at long wooden tables, townspeople purposefully gossiping.

It looks out upon a small Italianate piazza, and the town all around is built of dark grey granite, honeycombed with intricate lanes and thickly forested with chimneys. The neighbourhood was once frequented by a gang of robbers named the Red Bandits, and there was a gold rush here in the 19th century.

Less than 3,000 people live in this town. Two rivers water it. They have played cricket here since 1826. The ceiling of the parish church is held up by black wooden poles. There is a Carmelite convent with a dozen nuns in residence, and a Catholic church with a priest from Uganda. One resident has seen 25,000 different films, says the Guinness Book of Records.

At dinner last night I drank an ale brewed with heather honey, and ate an ice-cream flavoured with whisky and honeycomb. Today I might hire a guide to take me up a nearby mountain. Christian sectarians flourished here until they were driven out by bigotry, and fled to another country. There used to be fairies under one of the bridges.

Well, where am I? Spain? Brazil? The Orkneys? New Zealand? No: Dolgellau, a singular small town in the county of Gwynedd, more or less in the heart of Wales.

The mountain is Cadair Idris, nearly 3,000ft high, and in a way its presence defines Dolgellau. Its great dark mass is always there, rising a few miles south of the town and attended by many legends – they say if you sleep a night on its summit you will wake up either mad or a poet. In Victorian times Dolgellau served as a sort of base camp for Cadair expeditions, and there really were mountain guides to be hired: today various adventure enterprises will still oblige but most visitors walk up by themselves, having called in at the tourist office to ask the way.

The mountain still affects the style of the place because it is made of the same dark grey substance that is Dolgellau’s aesthetic. As was said long ago, mountain and town “bear a sort of family likeness”. It is true that many of Dolgellau’s buildings were once colour-washed, and today modern white houses are scattered around the edges of the town, but the small centre of it all, bounded by the rivers Wnion and Aran, is still a tight tumble of grey stones that might almost have fallen there in an avalanche.

As you wander its crinkled passages, out of that plaza-like main square from one urban cranny to another, grey stones all around you, tall grey walls above – as you potter about town you may sometimes imagine yourself to be in some immemorially ancient burgh. In fact, the buildings of Dolgellau are mostly Georgian and Victorian. The church whose tower is the tallest thing in town, the one with the wooden pillars, only dates from 1725, and scattered here and there are agreeable gardened villas that might well have suited Jane Austen. Even the former police station looks gentlemanly, while the stylish restaurant that served me that whisky-and-honey ice cream is a former dungeon of the town gaol.

But, actually, the overriding sensations of the town, to my mind, are strangely timeless. If it sometimes seems downright medieval, it is sometimes like something from the Industrial Revolution. Neither the Romans nor the Normans ever gave a logical shape to Dolgellau. The Welsh landowning gentry of later times supplied some elegant public spaces but left no predominant architectural style, while, except for individual houses and institutions, modern times have left no style at all. Even the railway, which came here in 1868, was gone by 1968.

One recent day I encountered, however, a living representative of the Dolgellau society that created today’s town. A courteous Welsh gentleman in his eighties, he is a survivor of a family that, through several generations, ran a tanning industry beside the river Aran, the eastern boundary of the old town. The business has closed but some of its structures remain, and he himself lives in a well-proportioned grey house with a garden. It looks a very comfortable home to me, and he seems a comfortably composed sort of man – characteristic I would imagine of the Welsh chapel families that set the style of Dolgellau a century or two ago.

For this small country community actually had an industrial revolution of its own. It was a mean enough market town until first the wool industry, then the tanning industry, adopted it around the start of the 19th century. I asked my kind informant if he knew the story about the fairies beneath the bridge, but he just said, “No”. There was not much nonsense, I would think, among the tanners and wool merchants of old Dolgellau, and their preferred architecture shows it. Theirs was a handsome legacy, but not perhaps light-hearted, and not always welcoming to strangers. In 1850, William Makepeace Thackeray wrote:

If ever you go to Dolgellau

Don’t stay at the Lion hotel,

For there’s nothing to put in your belly,

And the waiter don’t answer the bell.

I also asked my cicerone if was true that Quakers had been persecuted in Dolgellau, and he just said, “Yes”.

It is the most notorious reputation of the town. The Society of Friends flourished here in the 17th century, after a visit by the charismatic evangelist George Fox. People of all ranks joined the movement, and several country houses round about became known as Quaker centres.

Stone cottages on one of the town’s winding lanes

Just how the town turned against them I don’t know, and nowadays it is proud of the association: there is a Quaker museum behind the tourist office and Quaker meetings are held in a private house. But persecuted the Friends were then, in one way or another, and in 1686 they upped and left. Their leader was a Rowland Ellis from the house called Bryn Mawr: a hundred of them went with him to Pennsylvania, and the name of his home at Dolgellau is well-known in America to this day.

It often used to be said, perhaps as a result, that the town was unwelcoming to outsiders but sometimes it has had more reason to be. Remember that bustling coffee shop? In 1555 a grandee who lived on its site was kidnapped and murdered by the Red Bandits of Mawddwy, those out-of-town thugs. Then the 19th century briefly brought hundreds of miners and speculators to work the gold and silver deposits of the neighbouring hills: who can doubt that all too many an alien scoundrel frequented the Dolgellau pubs in those days? And despite the cricket club, down the centuries in this heartland of Wales, not all English people have been invariably welcome.

On the other hand, the fashion for the Picturesque, which became all the rage among the English upper classes in the 1780s, gave the town a new raison d’être that sustains it still. Wales was the focus of this craze, mid-Wales in particular, and Dolgellau fulfilled all its needs. There is a popular promenade from town, the Torrent Walk, which was specifically designed to Picturesque standards, and the town and its environs met all requirements (mountains, rushing rivers, bosky dells, peasants, with an exotic local language thrown in).

So a tourist industry was born. Many a villa was built to accommodate visitors and their servants. Thackeray’s Lion Hotel no longer functions but the Royal Ship, its rival around the corner, survives still, and is nowadays rivalled by many bed-and-breakfast places and one or two boutique establishments. Though there is still a thriving cattle market, tourism has overtaken agriculture as the prime occupation of this town, and for that it may thank the Picturesque.

All in all then, it is a most surprising little town.

For one surprise, walk up the road from the main square, and you will find a lovely small stone Catholic church, the one with the Ugandan incumbent. It was designed in 1963 by a Maltese predecessor of his, and dedicated to Our Lady of Seven Sorrows. The moving bronze crucifix above its door was made for it by a Milanese sculptor, and gentle sacred music plays perpetually inside.

For another surprise, come to Dolgellau in July, when Sesiwn Fawr, the Great Festival, brings hundreds of performers and thousands of fans to hear rock and traditional music from all over.

And for a third surprise – oh, for a third, and a fourth, and a fifth small Dolgellau astonishment, just try meandering through those cramped and tortuous streets, along the banks of the two rivers, into that evocative coffee shop, over the seven-arched bridge of the fairies, and see what you find for yourself.

Jan Morris stayed at Y Meirionnydd Hotel (double rooms from £75). For details on the area see www.visitsnowdonia.info

Copyright The Financial Times Limited 2017. All rights reserved. You may share using our article tools. Please don't cut articles from FT.com and redistribute by email or post to the web.