Constantine’s twin basilica at Trier

Archaeological excavations at Trier's cathedral have confirmed the existence of Constantine’s twin basilica, a monumental complex built between 326 and 348 AD on the ruins of an imperial palace. This discovery challenges earlier assumptions about the site's structure, revealing two longitudinal halls—each capable of holding 6000 people—connected by a three-aisled hall in the east and a square baptistery in the west. The north basilica, slightly larger with a monumental entrance, featured a polygonal structure interpreted as a memoria, while the south basilica retained its original form. Excavations also uncovered ceiling frescoes from an earlier palace, dating before 326 AD, which depict members of Constantine’s family, further validating the legend linking Helena, Constantine's mother, to the basilica's foundation. Unlike other fourth-century twin basilicas, the Trier complex stands out for its scale and significance, offering unique insights into Constantinian church architecture.

Rowe, R. T. (2010). Constantine’s twin basilica at Trier. University of British Columbia. https://doi.org/10.14288/1.0058308