Early reviewers of Byron's Manfred were troubled by one of the same features that has piqued the interest of readers and audiences from Byron's time to the present: its relentless and daring religious iconoclasm. Mingling references to Christian beliefs with figures and practices from many different traditions, among them Greek mythology, European witchcraft, and various "Oriental" religions, and seeming to treat them all with equal skepticism, Byron implicitly challenged one of the linchpins of English orthodoxy: the Established Church. In this essay, I pay special attention to the array of references to various Asian or "Oriental" motifs, including Zoroastrianism and Byron's debt to Montesquieu's representation of that religion in his Persian Letters. Manfred is not a work of literary Orientalism, yet its network of Orientalist references made a crucial aspect of its radical contemporary impact.