This is the first comparative study of lived Utopian communities in antiquity. The examined communities provide examples of somewhat successful utopian experiments that believe the twentieth century notion that the application of utopian ideals must always lead to dystopia or not work at all. Strong-minded individuals whose conversion to religious and philosophical ideas led them to reject their former world created radically communitarian groups based on their conception of the ideal life. Through their charismatic personalities, Pythagoras, the 'Teacher of righteousness' (an Essene), Pachomius and Proclus inspired groups of dedicated followers to live according to these same values. As leaders they simultaneously justified their religious authority and strengthened the moral and common purpose of the members of their community through education. Gradually their powerful ideals and the resulting communal practices seem to have mutually influenced one other. Over time each founder modified his community and its ideals according to its unique environment. Soon each community became larger and different roles within it became more specialized. However, it proved the Pythagoreans, Esseneans, Pachomians and late pagan Athenians attempted to always combine their ideals with concrete practice. Ancient communities continually strove to reach their founder's ideals. As each began to form, it required the dedication, hard work and financial support of its relatively few members. Ancient utopias were neither constructed in paradise nor through idleness. Mentoring future leadership constituted a crucial element in some of these communities. These regulations further transformed and regimented the daily living arrangements of members in each community. Hierarchy later became an important form of leadership but was also a source of friction within each utopian community. Certainly each community was defined by good and bad characteristics and achieved some measure of success. But their success in creating a framework within which members could achieve a considerable degree of concord would seem to be confirmed by their abilities to endure, at least for much of the time. As a result therefore of their perceived successes these communities inspired and influenced later ones. Each community survived for varying lengths of time depending on various internal and external factors. However, hostility from outsiders often proved detrimental to some ancient utopian communities.