These small, low-roofed stone chambers were Ireland's answer to the sauna, used for centuries as a form of folk medicine, particularly for the treatment of rheumatism and joint pain. The method was straightforward: a fire was lit inside the chamber, allowed to heat the stone walls thoroughly, then raked out. The user crawled in, sealed the low entrance behind them, and sweated in the residual heat before plunging into a nearby stream or pool. The practice was widespread enough that sweathouses, sometimes called tigh alluis in Irish, survive in various states of preservation across the country, yet they remain largely unsung compared to grander antiquities.