Henry Shepley, grandson of H. H. Richardson, provided the winning design submitted by the Boston firm of Coolidge and Shattuck in the 1920 competition for All Souls Church. The program for the church required that it “typify Unitarian ideas and ideals, harmonize with the architecture of Washington and fit into the surroundings of the chosen site.” The third Unitarian church to be erected in Washington (the first was by Charles Bulfinch), it is clearly based on James Gibbs's Saint Martin-in-the-Fields (1720–1727), one of the best known of English Baroque churches. However, a large service wing with courtyard set perpendicular to the church's main axis that extends and expands on the English model was integral to Shepley's design. Apparently Saint Martin's was deemed an appropriate prototype because numerous versions of it had been built in eighteenth-century America. Although not hitherto found in the Meridian Hill area, the Colonial Revival styles of architecture were well represented in other Washington neighborhoods by the early 1920s.