This paper considers the sources that inform W.B. Yeats’s conception of Unity of Being. Yeats expresses this concept in religious terms and syncretically aligns his ‘Christ’—his Unity of Being—with an amalgamation of belief and philosophical systems. In this paper, I focus on a triad of influences that Yeats frequently drew together: Dante, Blake, and the Upanishads. Through a reading of images from the poems ‘Ego Dominus Tuus’ and ‘The Phases of the Moon’, this paper hopes to enrich existing literature on Yeats’ religious self-conception as it stood at the publication of the second edition of A Vision. This article will explore how, since Yeats considered his pre-occupation with Unity of Being to be the origin of A Vision, the abovementioned poems are further connected to the background of Yeats’s fictional characters Michael Robartes and Owen Aherne through references to ‘Rosa Alchemica’ and Yeats’s play, Calvary.