This paper reassesses the archaeological evidence for the overall form of the church planned and in part built by the treasurer of St Martin’s abbey, Hervé, c.1001–1022. In particular it examines how the new chevet, built with a main apse surrounded by an ambulatory and radiating chapels, related to the design of other parts of the church. By way of background to the project, the preceding 10th-century history of the abbey is summarised, and the career of Hervé and his contemporary political context are reviewed. The chronology of the programme of work is assessed. Finally, the evidence is examined for the form of the shrine of St Martin, set in the new apse.