Original: Bernini created a large bronze throne in which it was housed, raised high on four looping supports held effortlessly by massive bronze statues of four Doctors of the Church, Saints Ambrose and Augustine representing the Latin Church and Athanasius and John Chrysostum the Greek Church.
Simplified: They are Saints Ambrose and Augustine for the Church of Rome and Saints Athanasius and John Chrysostum for the Orthodox Church.