1. Plan of the basilica of St. Paul in its original state, in the fourth century, in the time of Constantine and his successors, Valentinian II, Theodosius, Arcadius, and Honorius.
2. Transverse section of the same, showing the great arch between the nave and transepts, which was called the triumphal arch in the primitive churches, because the Christians were accustomed to trace in mosaic on these arches the triumphs of Christ, even as the pagans adorned their triumphal arches with the victories of their emperors.
3. Longitudinal section, showing the form of the ancient portico.
4. Plan of the church in the state in which it was prior to the fire, with the chapels, sacristies, and depôts, and other dependencies successively added; also the new portico, erected in 1725, under the pontificate of Benedict XIII.
5. Section of the transepts; the wall pierced with arcades dividing it throughout its length, is a later addition, which has very much changed the original form.
6. Exterior view of one of the sides as it appeared before the fire.
7. One of the trusses of the roof of the nave.
8. Longitudinal section of one division of the same roof.
9 and 10. Details of the truss.