Redrawing History - archeological accuracy
...the Via Flamina and its odd placement in the Campo Marzio. Fasolo refers to the placement of the Via Flaminia as arbitrary. This then also brings into question the positioning of the Equiria, (which Fasolo wrongly identified as a waterway) and how the Via Flaminia today is actually the route inscribed by the Equiria of the Campo Marzio, and how the present day Corso, whose name refers to the ancient race course (I still have to verify this) is not depicted within Piranesi's Campo Marzio but the "arbitrary" Via Flaminia seems to take its place as the "main street" of the redrawing.
...note the locations in the Campo Marzio where Piranesi actually did excavation--this information is available in Lanciani's Forma Urbis Romae.
There is also the connection between the big scoop on the bank of the Tiber (depicted on the Nolli plan) and the Natatio (beach) at the same location in the Campo Marzio.
...a comparison between the Minerva Medica and the Horti Luciliani. Piranesi may be, at times, loose with what he puts where and what the buildings look like, but he is consistent in terms of finding his inspiration in actual Roman buildings.
Pictorial Dictionary notes
Basilica Neptum, was between the Pantheon and the Porticus Septa Julia, Piranesi moves it to the other side of the Via Lati. It was badly injured in the fire under Titus in 80 AD; it was restored by Hadrian probably in conjunction with the reconstruction of the Pantheon; there is an existing drawing by Palladio and a fantasy reconstruction by Lanciani.
Sep. Honorij Imp.
sarcophagus of Maria
The only sketches which have reached us represent a few perfume bottles found inside the grave. Of these flacons there are two sets of drawings, one in a codex of marchese Raffaelli di Cingoli, f.43, with the legend, "Five goblets of agate discovered in the foundations of S. Peter's during the pontificate of Paul III. in the tomb of Maria, daughter of Stilicho and wife of Honorius;" the other in the codex of Fulvio Orsino, No. 3439 of the Vatican Library.
The discovery took place in 1544. A greater treasure of gems, gold, and precious objects has never been found in a single tomb. The beautiful empress was lying in a coffin of red granite, clothed in a state robe woven of gold. Of the same material were the veil, and the shroud which covered the head and breast. The melting of these materials produced a considerable amount of pure gold, its weight being variously stated at thirty-five or forty pounds. Bullinger puts it at eighty, with manifest exaggeration. At the right of the body was placed a casket of solid silver, full of goblets and smelling-bottles, cut in rock crystal, agate, and other precious stones. There were thirty in all, among which were two cups, one round, one oval, decorated with figures in high relief, of exquisite taste, and a lamp, made of gold and crystal, in the shape of a corrugated sea-shell, the hole for the oil being protected and concealed by a golden fly, which moved around a socket. There were also four golden vases, one of which was studded with gems.
In a second casket of gilded silver, placed at the left side, were found one hundred and fifty objects, -- gold rings with engraved stones, earrings, brooches, necklaces, buttons, hair-pins, etc. covered with emeralds, pearls, and sapphires; a golden nut, which opened in halves; a bulla which has been published in a special work by Mazzucchelli; and an emerald engraved with the bust of Honorius, valued at five hundred ducats. Silver objects were scarce; of these we find mentioned only a hairpin and a buckle of repoussť work.
The letters and names engraved on some pieces prove that they formed the mundus muliebris (wedding gifts) and toilet articles of Maria, Daughter of Stilicho and Serena, sister of Thermantia and Eucherius, and wife of the emperor Honorius. Besides the names of the four archangels -- Raphael, Gabriel, Michael and Uriel -- engraved on a band of gold, those of Domina Nostra Maria, and of Dominus Noster Honorius, were seen on other objects. The bulla was inscribed with the names of Honorius, Maria, Stilicho, Serena, Thermantia, and Eucherius, radiating in the form of a double cross with the exclamation "Vivatis!" between them. With the exception of this bulla, which was bought by Marchese Trivulzio of Milan, at the beginning of the present century, every article has disappeared. That the gold was melted, and that the precious stones were disposed of in various ways, so as to deprive them of their identity, is easy to understand, but where have the vases gone? Were it not for the rough sketches made at the time of the discovery we should not be able to form an idea of their beauty and elegance of shape. They were not the work of goldsmiths of the fifth century, but were of classical origin; in fact they represent a portion of the imperial state jewels, which Honorius had inherited from his predecessors, and which he had offered to Maria on her wedding day. Claudianus, the court poet, described them expressly as having sparkled on the breast and forehead of empresses in bygone days.
We know from Paul Diaconus that Honorius was laid to rest by the side his empress; his coffin, however, has never been found. It must still be concealed under the pavement of the modern church at the southern end of the transept, near the altar of the crucifixion of S. Peter.
Rodolfo Lanciani, Pagan and Christian Rome (New York: Houghton, Mifflin and Company, 1892), p. 203-205.