In East Asia, the religious and intellectual history of women has been less seriously dealt with compared to that of men. In Korea, the focus has been most often on elite men who reinforced Confucian patriarchal ideals. Unfortunately, the Confucian hierarchy excluded women from the intellectual world and reinforced inequality and double standards at all levels. This paper gives a voice to the marginalised women who converted to Catholicism during the late eighteenth/early nineteenth century, but who have, once more, been overlooked at the expense of elite men. It will firstly outline how Confucian constructions of “good” women subjugated and delimited their possibilities vis-à-vis men. By engaging with contemporary critical theory, it articulates how marginalised women, who took the lead in spreading the Catholic faith, risking, and often losing their lives in doing so, unsettled Confucian constructions as they endeavoured to realise a new value system based on the Christian teaching of equality: this was considered “dangerous knowledge,” and seen as a threat to the state. This study focuses on two women in particular: Colombe Kang Wansuk (1760-1801) and Luthgarde Yi Suni (1781?-1802), who show us various ways in which Catholicism was transforming the lives of women, dissolving rigid binary notions of gender, allowing everyone to participate in the intellectual and spiritual world through the use of Han’gŭl, as well as developing a new religious modus vivendi for women and men.