The Basilica of Saint Stephen in the Round in Rome, on the Celian Hill, was built in the 5th century and later consecrated by Pope Simplicius.
It was “the first church to rise within the urban perimeter and near the residential area, copying almost exactly the plan of Constantine’s Holy Sepulcher,” although it had “models and direct antecedents in Rome itself, such as the Basilica of Saint Constance – built by Constantine’s daughter soon after the sanctuaries in Jerusalem and Bethlehem, in the same architectural context and perhaps with the work of the same circuit of designers and workers” (translated from R. Salvarani, “La fortuna del Santo Sepolcro nel Medioevo”, Jaca Book, Milan 2008).
Author Alfredo Cattabiani explains, “the worship of Saint Stephen was so widespread in Italy during the Middle Ages that it inspired the name of no fewer than fifteen towns, from Santo Stefano Belbo to Santo Stefano Magra to Santo Stefano in Aspromonte.”
“Rome alone,” Cattabiani goes on, “had some thirty chapels and churches dedicated to the Protomartyr. The most famous still exists today, and was the Basilica of Saint Stephen in the Round on the Celian Hill: one of the capital city’s wonders of religious architecture, with its circular plan […] symbolizing Heavenly Jerusalem.”
“The popes led a solemn procession to the church every December 26th, to honor the martyr. Not knowing the date of Saint Stephen’s ‘dies natalis’, they had chosen to celebrate the first witness – mártys-mártyros in Greek – of Christ as close as possible to Christmas” (translated from A. Cattabiani, “Santi d’Italia”, Rizzoli, Milan 1993).