This dissertation aims to explore the practice of the care of the self in three Renaissance plays by means of Michel Foucault¡¦s theory of the technologies of the self derived from the Greco-Roman ethics of the care of the self. Foucault asserts that the Greek ethics of the care of the self offers a beneficial viewpoint to the modern investigation of freedom outside of sexual liberation. This study first constructs the guiding principles for the possible realization of the Greco-Roman ethics of the care of the self in other epochs, especially the early modern era. The technologies of the self are interconnected with the technologies of power, and their contact point resides in governmentality. The subject is shaped by the governing schema of the ruling authorities while concurrently being modified by the self through self-government. The subject must comprehend the governing tactics of the authorities in order not to be governed too much and can further govern other people for personal purposes. To be able to do so is to be equipped with a philosophical ethos of critique, which can be executed in three perspectives: thought ¡V an attitude of criticism, action ¡V the plebian quality, and words ¡V the practice of parrhesia. The study then applies the aforementioned guiding principles to discuss the three heroines in terms of the four aspects proposed by Foucault in the relationship to the self: the determination of the ethical substance, the mode of subjection, the means of ethical works, and the telso of the ethical subject. It investigates how the three heroines of different social statuses ¡V aristocrat, citizen, gentry ¡Vfulfill the practice of the care of the self through various strategies and unconventional life styles.