As one of the most tireless advocates of Modernism in the Church of England, Ernest William Barnes (1874–1953) was the subject of both veneration and scorn. The position Barnes adopted on evolution during the inter-war years, the period during which he was installed as the Bishop of Birmingham, has been the focus of recent scholarship. In particular, his spiritual agenda departed from those of most Modernists in that it encouraged the faithful to accept the precepts of evolution and Mendelism while it repudiated Lamarckian progressivism. Indeed, his unadulterated appreciation of neo-evolutionary theories makes it easier to understand his willingness to promote eugenic principles.Another unusual aspect of Barnes's Modernist theology, however, remains to be examined in any detail – namely its mathematical underpinnings. Before rising to his bishopric, Barnes was elected a Fellow of the Royal Society on the strength of his mathematical research. Further, his reputation as one knowledgeable in both modern mathematical and biological investigations provided an authoritative legitimacy that was meant to enhance his efforts at reconciliation, including his Gifford Lectures of 1927 to 1929. This paper examines Barnes's promotion of Riemannian geometry, especially as it relates to the consolation he found in the concept of a finite universe. Ultimately it asserts that mathematics made essential contributions to a cosmological perspective integral to his Modernism.