Both beginners and specialists in ancient studies often ask why bathing was so important to Roman society. This question might be an easy one, but there are no easy and definite answers. Bathing was a significant part of their lives, an institution rooted in the structure of their day. The Roman day normally reserved the afternoon for leisure. Already, by the end of the Republic, spending the latter part of the afternoon, after a light lunch and siesta, in the public baths had become a tradition, a comforting part of urban life and national identity. But why did bathing become a daily habit in the first place? The first and most important is the pleasure factor. At its most basic, bathing is physically and psychologically satisfying. Warm, moist air and water relax the body and clear the mind. Another factor that helps account for the popularity of baths is the well-entrenched belief in the ancient world that baths were good for health. Bathing was considered a serious therapeutic measure and received full support from ancient medicine. Finally there is also a basic economic explanation. Baths were built in such large numbers because running a public bath was seen a sensible lucrative business proposition.