The three churches designed and built by Nicholas Hawksmoor in the old London parish of Stepney (1714–1730) established his reputation as the leading architect of the late English Baroque. Christ Church Spitalfields, St George-in-the-East, and St Anne Limehouse were built in the Classical style, following the galleried basilica template established by Christopher Wren’s Church of St James, Piccadilly. However, their design seems to have been equally influenced by medieval design geometry. Laser-assisted surveys were undertaken at the three churches, measuring the significant dimensions and calculating the proportional relationships that define the interior space. At each church, the nave width was probably the starting point of the design, from which the other key dimensions were generated. The horizontal dimensions of the church plan likely established the vertical dimensions of the elevation. There is frequent use of the geometrically derived ratios 1:√2 and 1:√3. These were design procedures common in medieval Gothic architecture. Hawksmoor may have derived this combination of Classical and medieval influences from the City churches of Wren. The churches of both Hawksmoor and Wren suggest that medieval design knowledge and practice survived, perhaps as an oral tradition among builders, despite the dominance of the Classical style in early eighteenth-century Britain.