Last fall I travelled to a small Swiss backwater called Baden. Not Baden-Baden, the glitzy German spa, but another spa town famous since Roman times. Baden’s sulphureous springs promised relief from a raft of physical ailments – from infertility to rheumatism – but people more often travelled there in search of pleasure. Medieval Italians would stare goggle-eyed at the casual nudity of the men and women who ate, drank and flirted in Baden’s bathhouses. All that made for amusing reading, but it didn’t explain why the place kept beckoning. Perhaps it was the image of a medieval square ringed with 30 bathhouses or the melancholy sense that Baden had gone from being a hot spot to a has-been.

My cab trundled down Baden’s twisty streets and left me in the old bath quarter at the Hotel Limmathof, where a modern spa hotel had been fitted into two 19th-century buildings. The spa, a swanky mixture of luxe and industrial chic, included a two-chambered thermal bath, about the size of two generous hotel rooms, a cold room with a snow wall and an ice “table,” a steam bath, aroma grotto, sauna and resting room. It was a sybaritic smorgasbord that accommodated Roman, medieval and New Age ideas.

Seated at one end of the thermal bath on an undulating series of pipes, I pressed a button and water burbled energetically all over me. From there, I watched couples cavorting in the water, indulging in what my daughters call PDAs (public displays of affection). I felt part of a long historical tradition. Briefly, I was one with the medieval Italians who gaped at Baden’s bawdy bathers. It reminded me of a palimpsest, one of those ancient documents where earlier writings are partially visible underneath the newer ones. Baden, I thought, was also a bit of a palimpsest.

One difference between the medieval bathers and these youngish, well-heeled Moderns was that the 21st-century bathers wore swimsuits – everywhere, that is, except in the sauna. The first few times I stepped in and encountered naked bodies, I exited, worried that I’d stumbled into some private party. After the third try, I gave up, realizing I’d missed a vital piece of information. The English rules I’d been given by the receptionist made no mention of nudity, but later, on impulse, I asked her for the German version. There, obvious even with my nearly non-existent German, were regulations for the nacktzimmer (the naked room). Were they trying to restrict nudity to German speakers? Had long experience with stupefied Ausländer convinced Baden that foreigners couldn’t do nakedness?

In the square, around the corner from the Limmathof, a sulphureous smell announced two mementoes of Baden’s heyday – a trough where people can still dip their hands and arms in simmering water from Switzerland’s most mineral-laden springs, gratis, and a public drinking fountain with plastic cups. I filled one and took a determined swig of the rotten-egg-flavoured water.

The charm of this old bathhouse precinct had not prevented at least one failed hotel. I wondered about Baden’s economy and about modern Baden in general. A town of 16,000 where dress shops for dowagers and a boutique devoted to hemp kept close company was pleasingly opaque. Mostly, the remnants of the old bathing culture fascinated me, and I looked longingly at the handsome building (formerly the Inhalatorium) that housed the bathhouse archives. What a lost world would be conjured up behind those classical walls, at least for those who could read German.