Anthropologists have only started to investigate purity within the pastcentury. Most research has focused on living societies using ethnographic fieldmethods. Surprisingly, very few archaeologists have taken up the issue of purityin past societies, resulting in a lack of knowledge about its import inantiquity. This thesis, therefore, addresses this lacuna in research and setsout a broad framework for the archaeological investigation of purity in pastsocieties. This framework is illustrated using a case study from early Judaismin Roman-period Palestine. Between 300 BCE and 200 CE, ritual bathing in earlyJudaism grew in popularity. Two lines of evidence support this claim. First,ritual bathing installations (Hebrew: miqva'ot) were constructed throughoutRoman Palestine, several hundred of which have been recovered throughexcavation. Second, historical and legal evidence from the period comments onthe construction and use of these baths in purity rituals. Scholars who have studiedthis evidence have regularly stressed similarities in the physical features ofthese baths. Examining the size, staircase shape, building materials andtechniques, water storage, artifacts, and context from three well-excavatedbaths from Jerusalem, the Hasmonean Palaces in Wadi Qelt, and Sepphoris, thisthesis concludes that there was far more irregularity in bath construction anduse than previously assumed. The investigation of purity in past societies isan example of how archaeology can illustrate the contradictions betweencultural ideals and practices, linking this archaeological study to broaderanthropological concerns.