This chapter explores Iamblichus’ conception of theurgy as a universal mystical practice transcending religious and geographical boundaries. Positioning the theurgist as a ‘mystagogue of the ecumene’, Iamblichus advocated for communication with divine powers across cultural divides while preserving their unique identities. The chapter examines how Proclus embodied this cosmopolitan religiosity by honouring gods from diverse traditions. The discussion analyses three key elements of theurgic practice: the concept of ‘gods without borders’, where deities maintain individual significance while belonging to a unified divine order; the creation and use of ‘ensouled statues’ as physical receptacles for divine presence and the role of self-initiation and silence as essential modes of communication with the divine. Drawing connections between hermetic traditions, Egyptian ritual practices and Neoplatonic philosophy, the author demonstrates how Iamblichus sought to resignify religious ritual through a universalist framework. By examining textual evidence from Iamblichus’ Response to Porphyry, the Chaldean Oracles and magical papyri, the chapter approaches the function of theurgy as a self-initiation practice similar to those found in the Hermetic and magical traditions.