In ancient Rome there were 11 public baths, but as many as 951 were in private hands. In their publicity some of the private ones stressed their elegance and respectability, implying, a pool of modern experts has concluded, that some were of doubtful reputation.

In the rest of Lazio, the public ones were even more numerous, with 13 in the area around Viterbo alone, along a 12 km-long fault in the earths crust. The private places were myriad.

Today, in the whole of Lazio, a mere nine survive, nine being the number of spas or thermal baths in the region, the paltry sprinkling all still being fed by the same springs once tapped by the ancient Romans. Even the number of todays customers at the spas is derisory in the light of those in imperial times. In Rome itself, the Baths of Diocletian, the largest, could handle 3,000 bathers simultaneously, while the smaller Baths of Caracalla could cater for 6,500-8,000 people a day, but only if staggered in shifts of 1,600. Today the total capacity of Lazios two biggest spas is no more than an estimated 250. In Italy as a whole, the region does not shine. Luigi Minicillo, who is responsible for Lazios spas, confessed at the regions headquarters: Today were a bit behind other parts of the country. But Lazios baths, he said, had one virtue in common their restorative sulphur waters.

In ancient Rome, going to the baths figured large as a routine, democratic and social event, but though they might have known little of chemical formulae, the ancients were quite aware of the goodness of the water. The ever-poorly Emperor Augustus, for instance, suffered from arthritis and a bad liver and often had himself taken by litter for a cure to the nearby Baths of Tivoli; today this is the most accessible spa of Lazio, properly known as the Terme Acque Albule (albumen), due to the whitish water from the nearby twin volcanic lakes of Regina and Colonelle.

Today an airy, regal, turn-of-the century, vaguely Palladian-style spa centre, a pleasant place cheek-by-jowl with the deep local travertine quarries, boasts four outdoor thermal swimming pools set among eucalyptus trees and overlooked by the hills of Tivoli. They are vaunted as the most extensive in Europe, with changing-cabins for 1,080. In summer the young flock there, including those self-conscious with acne, all for 10 a day.

The sulphur in the water works on the skin, while breathing in its odours apparently gives a fillip to the lungs. Other services, available on the national health, include sulphurous mud-baths applied in individual cubicles as an antidote for rheumatic disorders, and the inhaling of vapour from spouts sticking out from the walls in a long room. We get 15-17,000 people a year here and we close for the winter, said smart Paola Pisanelli, a Tivoli resident who worked before at a congress centre. I dont know what they told you at the regione, but here were not slipping back. This year, our clients are up 20 per cent.

The second spa pole in Lazio, more snobby and for private patients only, lies near hot springs slightly to the north-west of Viterbo near its military airport, in a huge area today eerily littered with the remains of bath-houses once packed by the Latins and charmingly reviewed in the texts. Today the two surviving spas are within the grounds of two exclusive hotels; they do not come cheap and are a mite snooty, but what also sets them apart from Tivoli is the heat of their water.

The biggest, with 100 rooms, is the ultra-modern Grand Hotel Salus, which also calls itself Planet of Well-being (Pianeta Benessere), and its curiosity is a pool cooled to 35-38 degrees celsius that extends from within the hotel to the outside, even in freezing winter. The downstairs floor manager, Mariola Krzyzanowska, claims the place is full all the year round with clients aged from 30-90. This spa also helps with rheumatic complaints, osteo-arthrosis, fibrosis, a treatment for tired legs, and bronchial ailments, as well as offering beauty treatments.

The springs of both the Salus and the other luxury hotel, the 23-room Terme dei Papi, gush out of the same nearby sulphuric lake of Bullicame mentioned by Dante in the Inferno for its scalding (45 degrees celsius) temperature, as a simile for an unpleasant stream of boiling blood. At the Papi, the accent is on regenerative thermal dips and general rehabilitation, though it also offers a waterfall in a natural cave of its own beneath the floorboards.

With the descent of the barbarians into Italy, the spas were devastated and went into oblivion, to be rediscovered only in other parts of Europe, especially Germany and Flanders, around the 13th and 14th centuries. In Italy, states the tome produced by the region, the frowning of the Catholic Church on nudity and promiscuity held back the reopening of the baths until the Renaissance. Even the discovery by Pope Nicholas V in 1450 that waters in the Bagno della Grotta at Viterbo eased his gout didnt help the Lazio spas, which languished until well into the 19th century.

l Acque Albule, Tivoli. Via Tiburtina 22,700 km. Tel. 0774 / 35471, www.termediroma.com.

l Hotel Salus, Viterbo. Strada Tuscanese 26/28. Viterbo. Tel. 0761/ 3581, www.grandhoteltermesalus.com.

Other spas in northern Lazio.

l Stigliano (near Manziana); Musignano near Palombara Sabina; Cotilla and Antrodoco near Cittaducale.

Other spas in southern Lazio.

l Ferentino near Frosinone and Suio near S. Maria dei Lattari.

Note. Fiuggi is not mentioned in this list because people go there to drink the waters not swim in them.