My thesis, Identity and Plurality: Medicine in Ptolemaic Egypt, examines the various ways in which medicine was practised in Egypt between 332 and 30 BCE, the period when Egypt was ruled by the Greek family of the Ptolemies and there was a large Greek emigration into Egypt. The first chapter summarises the characteristics of Greek and Egyptian medicine before the Ptolemaic period. I show how the ideas and practices of both societies are affected by their cultural context. I then analyse the position of the Greek medical practitioner in Ptolemaic Egypt, and argue that institution of the medical tax assumed that Greek medicine was a distinctive part of Greek culture. I examine the numbers of practitioners in the countryside and towns, and their relationships with the governing administration. Finally I consider the role of folk medicine in GrecoEgyptian societies and possible interactions between Greek and Egyptian practitioners. The second chapter explores temple medicine. I investigate the practice of incubation in Egyptian temples, and show that while Greek and Egyptian preconceptions in this area were generally compatible there were also subtle differences in their expectations. The Greek perceptions of Egyptian cults and gods, in particular the Greco-Egyptian god Sarapis are investigated, and I analyse the numbers and social status of pilgrims. Finally I show that there may have been limited interest in Greek medicine on the part of the Egyptian temples, but that overall Greeks reacted and adapted t9 Egyptian institutions and practices. The third chapter analyses the Alexandrian anatomists Herophilos and Erasistratos and the Empiricist, Herophilean and Erasistratean 'sects'. Having analysed trends in the history of Greek theoretical medicine I demonstrate how Herophilos' and Erasistratos' views can be seen as developments of these trends to the point where they became exclusive alternates, and how this led to the development of the medical sects. Finally I examine the proposed candidates for Egyptian influence on the Alexandrian anatomists, and propose that the visible monuments of pharaonic culture may have indirectly affected Alexandrian mechanical and medical discourse. The fourth chapter explores the perceptions of healing and the healer in Qreek society. In particular it analyses how poisons, power and the discovery of plants were used to construct Hellenistic models of the good and bad king; how Hellenistic poets and writers used medical images and ideas; and how the advice and warning of the Hippocratic writers and the stereotypes of popular literature about the behaviour of physicians clarify the concerns of Greek society about medical power. In conclusion I argue that the study of medicine in the ancient world ancient offers the opportunity to examine societies though the plurality of approaches and attitudes to a subject of inescapable importance. This is particularly so in Ptolemaic Egypt, where healing was not simply part of two cultures but a means by which they interacted. Ethnic, social, intellectual and moral identity was partially constructed through the choices of patients and healers, and medicine was an arena of competitive cultural and individual expression.