My paper focuses on one of the most influential, but hardly explored, scholar of the phyi dar period *Jñānākara (eleventh century). *Jñānākara’s *Mantrāvatāra (An Introduction to the [Path of] Mantra) and his auto-commentary, *Mantrāvatāra-vṛtti, which have been lost in the original Sanskrit, but can be accessed in Tibetan translation as Gsang sngags la ’jug pa and Gsang sngags la ’jug pa’i ’grel pa respectively, provides a comprehensive picture of doctrinal debate that dominated the scene in the intellectual history of the eleventh-century Indo-Tibetan world, through demonstrating various perspectives on tantric practices that were forced to enter the battlefield of a critical discussion during the ‘tantric age’. The paper will try to reconstruct the most controversial issues of this debate, such as ‘cenobitic fornication’—that is whether monks should obtain tantric initiation and engage in the practices in which copulation was a central part—and the so-called wrathful rites (mngon spyod). Motivated by polemical ends, *Jñānākara’s *Mantrāvatāra aims at establishing its self-authenticity and preeminence by contrasting its ‘correct tantric practice’ with the so-called ‘perverse tantric practice’ promoted by ‘frauds’ and attributing to them, often pejoratively, erroneous or willful misappropriation of tantric scriptures. In this context, the making of orthodoxy goes hand in hand with questioning the legitimacy of certain tantric practices.