The Hellenic Association of Boston (founded in 1904) commissioned Worcester architect Hachadoor S. Demoorjian to design a Classical Revival church on a Byzantine-influenced plan—evident in the low central dome and four domed corner towers. The top two floors of the cathedral contain the sanctuary, approached from a two-level vestibule on the Parker Street side. After Demoorjian's death in 1925, Ralph Adams Cram advised on the interior decoration, hiring Evangelos Ionnides, a church member, to paint three Byzantine-derived murals and the dome. In 1935, Kenneth Conant, a Harvard professor of medieval architectural history (and recent convert to the Greek Orthodox faith) commissioned Charles Connick Jr. to create decorative glass for the sanctuary. Cram, Conant, and Connick, all members of the Medieval Academy of America (founded in Cambridge in 1925), saw the Greek Orthodox Cathedral of New England as an opportunity to introduce Byzantine forms to American church architecture. Despite the diaspora of Greek Americans to the suburbs beginning in the 1950s, the cathedral continues as a powerful symbol of this ethnic community in Boston.