At the dawn of the second millennium after Christ a great challenge appeared on the horizon of India’s northern borders, a challenge that over the next few centuries became clearly defined and assumed the shape of a political, social and cultural conquest whose dimensions are well known. The first to register the peril that the earliest Islamic incursions meant for Indian society were the authors of the Kālacakratantra literary corpus, the last tantric cycle of medieval Indian Buddhism. Together with historical and ethnographic elements linked to the observation of the customs of those “others” with whom the Indians had come in contact, what emerges in their writings is fear of the danger represented by Islamic people, who are depicted as an overwhelming irruption of evil, a demonic danger that threatens to utterly eclipse the Buddhist teaching. The terrible clash of civilisations toward which the Buddhist Indians were heading takes the mythical dimension of a devastating, apocalyptic fury of cosmic magnitude. In the Kālacakra eschatology, the historical events are transfigured in the final battle between the forces of good and evil, when a Buddhist Messiah with magical spiritual powers will bring about a new cosmic age of peace and perfection in the mythical land of Śambala. In this lecture we will explore the representation of Islam as it emerges from the Kālacakra literature and reflect upon its nature and origin.