Old Istanbul's bath houses hosted scheming Pashas and shapely concubines before modern bathrooms sent them into decline, but their appeal to tourists and the growth of the spa industry promise a revival.

Developers are spending millions of dollars buying and restoring Istanbul's finest hamams, or steam baths, after decades of neglect. They are banking on rising tourist numbers and a surge of interest among Turks in Ottoman customs.

“There is a good future for hamams. People have realised they are a strong business and there is a lot of interest in buying or managing them,” said Aydin Bulut, manager of the Suleymaniye hamam. His bath was built in 1557 by Mimar Sinan, the prolific architect behind Istanbul's most celebrated structures.

Price tags are high. Istanbul's Cagaloglu Hamam -- built in 1741 and boasting Germany's Kaiser Wilhelm II and Florence Nightingale among visitors - is on sale for $16 million according to estate agents Remax Turkey.

The smaller Ayakapi hamam, also built by Sinan but not currently used as a bath, is for sale for $3 million, they said.

The success of the handful of tourist-focused historic baths including the Cagaloglu, where a scrub and massage can cost up to $55, has persuaded developers of the business potential of Istanbul's dozens of other hamams.The baths' revival reflects a wider pattern of resurgent interest in Ottoman life in Turkey, a state founded in 1923 after the chaotic collapse of the Ottoman Empire. In its early decades it emphasised modernity and break with tradition.

“Since the 1980s everything Ottoman has been in vogue,” said Nina Ergin, an Ottoman expert at Istanbul's Koc University.

“At first the revival was orientated to tourists, but then people started to realise the value of Ottoman artefacts and traditions and wanted to find out more about their own past.” For example, scores of tourists and Turks alike now puff on water pipes, or nargiles, which were once deemed obsolete due to the development of the cigarette.

Interest in hamams also dovetails with a rising “spa and wellness” trend in Turkey, Ergin added.

No official figures are available for the value of the spa and hamam industry but Zeki Karagulle the director of Turkey's Spa Association said visitor numbers were increasing.

Hamams are recognisable by their thick stone walls, domed roofs and series of cupolas. Once inside, visitors relax in a hot, humid marble chamber lit by shafts of light from above, and allow the moisture to soften and penetrate their skin.

An attendant swathed in a traditional chequered sheet, called a pestemal, then scrubs the body vigorously with an abrasive cloth - removing dead skin and leaving the layer beneath so smooth it gleams.

An invigorating dousing with water follows, and visitors are left to stretch out on the hot marble stone at the centre of the chamber, heated from beneath by air circulating from a wood-burning furnace.

The look of bliss on their faces speaks for itself.

The hamam tradition developed in Muslim countries where Islam emphasised cleanliness and washing, but independently they fulfilled an important social function, with men and women spending hours inside gossiping and relaxing.Sometimes, as in the case of the Kilic Ali Pasa hamam, they were part of a mosque complex, hence their magnificent architecture they were intended to provide an income source to the religious institutions through entrance fees.

“For women especially, they were a place to get away from their families and if a husband couldn't pay for a trip to the hamam at least once every two weeks it was a ground for divorce,” said Ergin. “They were a very important space like a beauty salon or a spa today.” Brides would meet female friends in hamams ahead of their weddings, and the Sultan's concubines and favourites would take to the hamam to make themselves most fragrant and alluring.

For men it was a place to socialise and repose - also reputedly to indulge in more decadent pleasures. Sultan Selim II is said to have died in 1574 after slipping and banging his head in a hamam while drunk.

Turkey's restored hamams are set to be much more refined.—Reuters