Interior view

The Basilica of St Stephen in the Round on the Celian Hill commonly named Santo Stefano Rotondo, is Hungary's "national church" in Rome, dedicated to both St Stephen, the Christian martyr, and Stephen I, the sanctified first king of Hungary who imposed Christianity on his subjects. The church was originally commissioned by Pope Leo I (440-461) and consecrated by Pope Simplicius between 468 and 483.

The original church had three concentric ambulatories flanked by 22 Ionic columns, surrounding the central circular space surmounted by a tambour that is 22 m high and 22 m wide. There were 22 windows in the tambour but most of them were walled up in the 15th century restoration. The central ambulatory had a diameter of 42 m, and the outer one a diameter of 66 m. Four side chapels extended from the middle ambulatory to the outer ambulatory, forming a Greek cross.

The walls of the church are decorated with numerous frescoes, including those of Niccolò and Antonio Tempesta portraying 34 scenes of martyrdom, commissioned by Gregory XIII in the 16th century. Each painting has a titulus or inscription explaining the scene and giving the name of the emperor who ordered the execution, as well as a quotation from the Bible.

View the cross section and ground plan of the building.