How did bath houses become popular

Bathing and concepts of cleanliness are not universal across societies. Cleanliness, for some, meant multiple times during a day bathing, while for others it may simply have a religious or spiritual significance, even while little bathing took place on a day-to-day schedule. For most of human history, private bath facilities were a rare commodity. Thus, it is the history of bath houses that is associated with social concepts of cleanliness and this was spread by factors that included empires, new religious/spiritual ideas, and other cultural influence.

Early Bath Houses

Perhaps among the earliest societies with bath houses included Indus region societies in the 3rd millennium BCE, who built forms of bath houses and established rituals for bathing. In fact, one the earliest large bathing, and likely public, complexes is found in Mohenjo-daro, where the so-called "Great Bath" is often considered the earliest public bath with the main pool measuring 11.88 × 7.01. Later Indian works, such as the grihya sutras, discuss the importance of bathing and hygiene that emphasized bathing three times a day as a way to keep the body clean. It was also seen as a way to stay spiritually clean, demonstrating that religious concepts of cleanliness sometimes were associated with physical cleanliness.

Both ancient Mesopotamia and Egypt have evidence for bathing in private spaces, such as homes and palaces, but public bathhouses are largely absent. In second millennium BCE, Akrotiri in Santorini and Knossos in Crete show evidence there were bathing facilities, although these, similar to Mesopotamia and Egypt, may have been for more wealthier individuals or classes. In fact, daily washing in a bathroom may have meant you were wealthy enough to have these facilities in your own private space. In Greece from the first millennium BCE, bathing had a more public aspect, perhaps similar to ancient Indian/Indus cultures. As the Greeks emphasized sports that meant participants were generally naked, where our modern term gymnasium comes from, communal baths for the competitors were required. Even some of the earliest showers may have developed in baths used for athletes between 500-300 BCE.

Later Bath Houses

As aqueducts and water supply technologies, such as qanats became more elaborate, public baths developed in more places.