The study focusses on literary representations of three categories of ideal friendship - Christian, chivalric, and humanistic - and the writers' strategies of establishing the ethical authority of their contemporary friends and codes on a par with antiquity's amicitia perfecta. The study identifies the extent to which writers acknowledged women as perfect friends. The selected texts under examination include, among others, hagiographies, works of Bernard of Clairvaux and Aelred of Rievaulx, The Quest of the Holy Grail, Thomas' Tristan, the Prose Lancelot, Ami and Amile, the Decameron, and L.B. Alberti's Dell' amicizia. Literary comparatists and historians, ethical historians, and students of rhetoric will find of interest the comparative study of the rhetorical topos of perfect friendship, the varied ethical criteria inherent there, and the writers' strategies for representing and authorizing an idea.