The present study explores the ideal of the holy person in Indo-Tibetan Buddhism from the dual perspective of inner realization and of public recognition or cult. Our investigation begins with the Arhat of Early Buddhism, who has cleansed away all past defilements and their effects in the present, who manifests supranormal knowledge and power, and who is a 'field of merit' worthy of veneration. With the rise of Mahayana Buddhism, the earlier model of holiness was subjected to criticism in the light of a new ideal, the Bodhisattva, who practices a path toward selflessness that includes commitment to a vow not to enter the supreme state of Nirvana until all beings have, with his help, entered therein. The Bodhisattva ideal underwent further transformation in the context of tantric Buddhism in the remarkable figure of the Mahasiddha during the period of the transmission of Buddhism to Tibet. The Buddhist tantras provide us with an exemplary figure, Vajradhara, who represents the state of supreme Enlightenment. Vajradhara is a powerful symbol for the assimilation of the Saint, the Guru, and the ritual hierophant into a single object of devotion by which the practitioner may strive to attain the highest spiritual state 'in a single body, in one lifetime.' Using a thirteenth century account of Vajradhara as a theoretical framework for holiness in the tradition of the Buddhist tantras, we present an historical, doctrinal, and literary analysis of the biographical tradition of Milarepa, a Tibetan poet and Saint (1040?-1123), taking into account works earlier than the well-known rnam thar and mgur 'bum by gTsang smyon Heruka (ca. 1488). Translations of the account of Vajradhara and of the biography of Milarepa by rGyal Thang pa, a thirteenth century bKa' brgyud pa master, constitute Part III of the dissertation.