Stables, mangers and cattle a-lowing do not feature prominently on Finnish Christmas cards. The inhabitants of this beautiful, frozen-solid country believe Jesus was born in their own personal idea of heaven on earth: a sauna.
If it's good enough for the Messiah, it's good enough for me. So when a research trip took me to Helsinki this year, I saw an opportunity to indulge my passion for getting naked with strangers and steaming or boiling myself to nirvana. I picked up the habit while living in Japan, a country leaking all over with hot springs, but it's an art that most Brits, who sit beet-cheeked and sweating in nylon-elastane swimsuits heavy with chlorine, simply don't appreciate.
The Helsinki apartment block where I stayed boasted its own sauna - as essential as the communal laundry room and the recycling bins - and I spent many pleasant evenings there refreshed by jugs of chilled strawberry squash. However, the serious study didn't begin until I visited the birch-grove island fastness of the Finnish Sauna Society, home to three venerable savusauna (smoke-saunas), an electric sauna and - testimony to the depth of their devotion - a research sauna used by scientists investigating its health-giving properties. Now that's a PhD I wish I'd written.
The society's executive director, Heikka Heimonen, gave me a potted history. The earliest known sauna is 6,000 years old, a covered pit containing a firehole filled with stones. In more recent centuries, the sauna was the part of the house used for drying linen, smoking meat and, yes, giving birth: the only place warm enough to keep a baby alive through a Finnish winter. In those days, the usual sauna temperature was a sedate 50-60°C; today, the range is 80-100°C.
The FSS saunas all had small windows, through which you could see scenes of what looked like torment à la Bosch, or perhaps a madhouse cell. One smoke-blackened slot disclosed a self-flagellant wielding a birch switch vasta fiercely enough to atone for endless past lives of sin. The vasta is the answer to a ribald traditional riddle, "An ell of hairy stuff, and a handle's length of bare," but the smutty reputation that saunas once enjoyed among more uptight nations is not deserved. Public saunas operate sex-segregation, and even in families men may steam separately from women.
Sufficiently warmed over, I headed to the sea shore for a brief avantouinti, or ice-hole dip. The drill was simple: down the steps and in, kick out, turn back, shiver and shudder. This year is the first on record that the FSS has not had to break the sea ice at its plunge station, but it still very nearly finished me off. I went in bright red and emerged a blotchy purple, my heartbeat frantic. Taking no chances, I headed for the re laxation room and thawed out by the roaring hearth while enjoying beetroot pie. I watched a pro cession of bathers emerge from the sauna into the freezing air wearing nothing but steam, like so many biblical pillars of cloud.
Ice had been part of my sauna vision - I wanted to experience the full 100°, hot-to-cold body-shock. (How I envy members of the 300 Club, those Antarctic workers who - albeit by cheating in Fahrenheit - emerge from a 200°F sauna and sprint nude to the South Pole in temperatures of -100°F.) So when my fortnight in Helsinki was up, I flew over the Arctic Circle into Lapland. I was going north to learn to drive sled dogs, but pictured myself bobbing seal-like, cold-proofed by a sauna, in the frozen river that separates Finland from Sweden.
Arriving late, under a feeble curdling of light that was the best the aurora borealis mustered during my visit, I went straight to the resort's riverside sauna only to find that its fires had long since died. It contained a figure that I at first mistook for the sauna gnome - a household deity that a perspicacious peasant described in 1909 as being black and having only one eye. But no, this hoary cove was pink, not black, and the missing eye turned out to be winked shut in a leering appraisal. I obviously wasn't up to scratch, because a few minutes later he stretched lazily, displaying his withered vasta, and shuffled out.
I stayed in the tepid sauna for a few more minutes before conceding defeat: I've sat on steamier Tube trains. Advised by a passing guest to try the hot tub instead, I tottered, wrapped in my cotton dressing gown, towards the sound of distant shrieks. It was the sauna gnome, with a bevvy of naked ladies and bearded young men drinking beer. (Hot tubs have, forever and amen, lacked the moral code of the sauna.)
The tub was also tepid, but the gnome was doing his best to heat things up. "I am Father Christmas," he boomed, pulling a wriggling nymph ette on to his lap, "and this is my favourite elf!" He was, too: his December job was entertaining visiting children on £2,000 trips to Lapland, though not, one hopes, in hot tubs. I lasted five minutes before my hair froze in an icy sheet and climbed out reluctantly to find that my dressing gown had also frozen. The Finns have a pro verb even for this: "Cold are strange saunas."
It was to be another day before I found my nirvana - a day spent literally harnessing the energies of a dog team as we kicked uphill and sped across a frozen lake. The night stop was at a wilderness hut, complete with sauna. We fired up the wood stove, then spent two hours un fastening, bedding down and feeding the dogs. With a new understanding of the term "dog-tired" (anyone who thinks the huskies do all the work is sorely mistaken), I crawled into the lopsided sauna shed and was enveloped in a cloud of blissful steam.
If Jesus was born in a sauna, then pious Finnish peasants could find no better simile for his mother's blessing than its steam. A 17th-century Finnish poem by Anonymous begs Mary to "throw honeyed vapour, like vapour in a sauna", on her weary devotees. As the dogs whined and sang in the dark outside, I felt truly blessed.