The Arch of Tiberius has never been reconstructed other than by physical models, this doesn't mean that it cannot be done. In this paper, I will discuss the history of the arch and how it truly looked. Keywords: fornix, Germanicus, Varus, Teutonberg, Saturn, Basilica Julia, Sacra Via, Roman Forum, Constantine, Richardson, stair, Corinthian, columns, frieze, Tiberian attic, Ware, pedestal, Tacitus, Nash
This comes from my own published work called "The Once and Future Forum: Approaching Virtual Reconstructions as an Archaeological Tool"
ARCH of TIBERIUS
[Arcus Tiberii]
The Arch of Tiberius was a single-fornix arch erected in AD 16 to commemorate Germanicus’ recovery of the standards of Varus captured by the Germans in the battle of Teutonberg in AD 9.55 It stood proper aedem Saturni near the northwest corner of the Basilica Julia beside the Sacra Via along the southwest side of the Roman Forum, which narrows to accommodate the arch. The arch is represented on a relief of the Arch of Constantine.
Richardson suggests the Arch of Tiberius stood above the level of the street and “probably could be reached only by a stair of a few steps.”56 The attic inscription was recovered in fragments (CIL VI.906, 1269, 31422, 31575a) from an 1833 excavation, and the marble foundations found in 1900 were 9 m. wide and 6.3 m. deep.57
As can be seen on the relief from the Arch of Constantine (see figure 6.1), the Arch of Tiberius had Corinthian columns that reached to the frieze. Though there is neither inscription provided nor a plaque, the attic fragments suggest there was one. It can only be supposed that the artist for the relief failed to give the Tiberian attic a proper proportion.
Temple of Vespasian
The Author’s Arch of Tiberius
Other than the arch that the author reconstructed, there are currently no virtual models of the Arch of Tiberius. Since the marble foundations were 9 m. deep and 6.3 wide, the virtual reconstruction was based on this measurement. Following a chart influenced by Ware’s work, the pedestal’s height is 1/3rd the columns‘ height including the capital (see figure 6.1). The pedestal’s width is usually 4/3rd the column‘s bottom diameter (abbreviated further as D). The capital is the height of 7/6th D and 3/2 D wide. When the relief from the Arch of Constantine is examined and measured the column’s top diameter is 19 pixels across. According to Ware, the column top is 5/6th the diameter of a column. This calculates that the D is 22.8 pixels in the picture. We now know that the pedestal’s height is 68.4 pixels (3 D) and its width is 30.4 pixels. Ware explains that the center of each Corinthian column is 8 2/3rds D from an arch’s center. Each side of
the pedestal’s crown and base project out from the pedestal 1/9th the pedestal’s height. Calculating the sum we should get the width that equals 9 m.58
Since the relief’s 22.8 pixel column should be 1.1235 m., this model should be the same, but the column’s length falls short. The created column has a 0.9895 m. diameter. This is 12% short, which could arise from inaccurate measuring or missing one blurry pixel. It is also 5.56 m. tall while the relief, according to Ware’s statistics, suggests that the column is 9.55 m. tall. Re-examining the columns and making them 9.55 m. tall and expanding the pilasters to adjust, would present the arch with extremely tall legs - a site that this author has never witnessed for Roman arches. Though this model’s Corinthian capital is disproportionate and rather stout, I suspect that Ware’s proportion for arches is only relevant to arches within buildings such as basilicas (see figure 6.2). His proportion for the Corinthian arch’s width as 46.67% the height would make the arch 19.28 m. tall. This is far too tall for a single-standing arch.
Ware writes that the attic is generally one-fourth the height of the order below but should never be any taller than one-third. Measuring the relief’s attic, it comes to 44 pixels, which I estimate as 2.17 m. My attic is 2.2857 m. high. My arch falls within the range, but has a taller attic than it should. Based on the proportions seen on the relief from the Arch of Constantine, the arch can be built with some credibility. The Corinthian columns including crown would be around 6.935 m. tall, 0.73 m. wide. My arch is 11.3067 m. tall.
Arch of Tiberius reconstructed in Form-Z (left) and the relief on the Arch of Constantine (right).
^58
8 2/3 cD (columns from the arch center) + 4/3 cD (the extension of half a pedestal on each side) + 1/9 cD (the distance the pedestals’ crowns stick out on each side) = 9 m. Adding it all together shows us that 10 1/9 cD is 9 m. or that the cD is 1.1235 m.
The Arch of Tiberius reconstructed in Form-Z by the author. A side view (left) and front (right).
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Featured February 7 , 2007
