The sweathouses of Ireland date back to the 9th century and earlier. Now known as Bronze Age sweathouses, these ritual spaces were generally believed to have been used exclusively for healing and ritual purification.
Archaeologist Aidan Harte is leading the new Leitrim Sweathouse Project with Leitrim County Council Heritage Officer Sarah Malone. Malone said their aim was to identify and demystify these timeworn structures, which are scattered across Ireland and were used as a sort of stone sauna right up until the early 1900s. She said they had so far recorded more than 100 sweathouses in Leitrim alone – more than anywhere else in Ireland - a staggering concentration given that this tiny county is home to fewer than 35,000 people.
For generations, most of these mysterious beehive-shaped structures have sat dormant and forgotten. According to Harte, that's because many of the sweathouses are on properties owned by farmers who know little about them. Inhabited for more than 10,000 years, Ireland is laden with so many archaeological sites that they can't all be pinpointed, probed and preserved. Now, the Leitrim Sweathouse Project is seeking volunteers to collate information and oral histories on this little-known aspect of Ireland's history.
As with the one in Killadiskert, most Irish sweathouses were built into hillsides or banks to bolster their foundation, and set in remote locations near a water source. Chunks of uncut rock, each a different shape and size, were carefully piled and then bonded with clay and sod to create a domed structure with a single low entrance, similar in appearance to a beehive or igloo.
Turf or wood was lit inside the sweathouse, before its entrance and roof vent were blocked, Harte said. After a few hours, smoke would be released, the embers swept out and a naked person would crawl into the stifling heat and sweat for as long as they could bear. Eventually, they would emerge to cleanse and cool themselves in the nearby stream.
While sweating certainly has proven medical benefits – including helping to improve blood circulation and filter toxins out of the body – according to Dr Ronan Foley, a leading expert on Irish sweathouses from Ireland's Maynooth University, these sauna sessions were often nothing more than a placebo. "It would be very reasonable to assume the sweathouse cure did not work all the time or for all people, even for the conditions it was recommended for, so it was never a panacea in that sense," Foley said.
Yet, in Ireland's isolated landscape, where modern medical facilities were few and far between, sweathouses remained popular for hundreds of years. Foley said they were commonly used to treat rheumatism, arthritis, fevers and respiratory conditions, especially in rural areas like Leitrim, which is home to more than one-third of Ireland's identified sweathouses. By comparison, very few are located near the cities of Dublin, Cork and Limerick, which had far more sophisticated health services than Leitrim until recent decades.
Not much has been documented about the historical use of sweathouses. But many Leitrim families have ancestral roots that stretch back centuries, and thanks to Ireland's strong tradition of oral history, many sweathouse myths survive. Harte said some Leitrim residents he'd interviewed believe sweathouses weren't just used to treat illnesses.
According to some tales he'd heard, sweathouses were makeshift distilleries for circumventing Ireland's long ban on distilling "poitin" (moonshine). In another popular story, the structures hosted drug-fuelled hallucination sessions aimed at connecting with the Celtic gods. Harte doesn't give much credence to these narratives, and has found no evidence to support them. But with so little known about sweathouses, he also said he also can't rule them out.
An even greater mystery than the use of sweathouses is their origin. According to Foley, there are four prevailing theories. One claims these structures can be traced to Scandinavia and the Vikings. Saunas have been used in northern Europe for more than 2,000 years, and Vikings had a major impact on Irish culture while occupying parts of the country between the 9th and 12th centuries. Another theory posits they may have been imported from the US by returning Irish immigrants who'd studied Native American sweat lodges. Just as intriguing is the theory sweathouses were re-purposed fulacht fiadh, a type of ancient, outdoor Irish oven and ritual cooking space. Finally, some old antiquarian journals suggested the Irish creators of the sweathouse may have been inspired by seeing hammams while travelling in the Middle East, where the Islamic bathhouses have been used for more than a millennium.
Yet, none of these theories convince Foley. Instead, he believes Ireland's sweathouses emerged organically. "I feel they were a sort of local variant of a global cultural production of sweating-cure places," he said. "The healing value of sweating was well known. Building small buildings that induced sweating from local materials would have been sort of worked out by Irish rural dwellers."
Today, Ireland's ancient sweathouses are valuable artefacts of the country's rural history. Harte's project could even help these long-neglected structures become offbeat tourist attractions, according to Sarah McCarthy, a regional development officer for Fáilte Ireland, the country's national tourism body. "We know that culture and heritage form a significant element of Ireland's appeal to overseas visitors," McCarthy said. "The Leitrim sweathouses and the associated research project reveal a hidden part of our history and heritage, and add to the riches for the visitor to uncover."
Harte shares this hope. But as he bent down to peek into the tight opening of the Killadiskert sweathouse, he conceded most of these structures aren't yet ready to accommodate tourists. While tourists are able to gain direct access to the nearby sweathouses at St Hughes well and Parke's Castle, Killadiskert sweathouse and many others are on private land. Even as an archaeologist, Harte hadn't always found it easy getting permission from landowners to visit other sweathouses. A key aim of the Leitrim Sweathouse Project is to gain greater public recognition and heritage protection for these structures.
One day, Ireland's ancient saunas may be renowned, preserved and pinned to a tourist trail. For now, however, they remain enigmatic stone structures hidden in the emerald landscape, waiting for someone to unravel their secrets.