Ok now still sitting behind the Rostra, ya might have to stand up to see it :-) or just take that uphill street about 40 m to the Portico structure on the right (on the left side of the Temple of Vespasian and Titus).
They don't know much about it or what it was actually called in ancient times so the archaeologists have named it the 'Portico of the Dei Consentes' (aka 'Porticus Deorum Consentium') for the Counselor Gods and Goddess' that were displayed here in the form of twelve gilded bronze statues (From here on I am just going to write Gods/ess for Gods and Goddess'). These Gods/ess were the Roman version of the twelve Athenian Gods/ess and were paired-off one Male God to one Female Goddess (Jupiter-Juno, Neptune-Minerva, Apollo-Diana, Mars-Venus, Vulcan-Vesta, Mercury-Ceres).
Basically what you see today is from the first Century AD rebuild and later restorations. This 'rebuild' was very likely by Vespasian's boys because it *seems* that when they built dad's temple it cut into this area so they had to shorten up this Portico.
This Cult of Gods/ess was likely introduced to the Romans in the Late third Century BC, around the time of Hannibal's second Punic War. In 174 BC according to Livy a Portico once ran from the Temple of Saturn (the one with eight columns next to you) over to the Senaculum (now beneath that present-day church you see on the other side of the Arch of Septimius Severus). This portico really dressed up this end of the Forum serving as a nice backdrop.
From what *I* gather they think that this Portico perhaps originally held the twelve Gods/ess statues spaced along its length? Now when they built (121 BC) the Temple of Concord and the Basilica Opimia it would have very likely cut-off that section. But it was possibly still intact up to the Temple of Concord. So the Vespasian boys would have had to remove that section of portico in order to build the Temple of Vespasian. So now they only have a short section of the original portico left on the side of the Temple but still have twelve Gods/ess to house. So it seems that the boys rebuilt this Portico section to house the twelve within this now very limited space. And at this point it's more like a Shrine rather than a functional everyday Portico which is basically a covered walkway.
Now if a run-of-the-mill Portico was in the way of their Temple they would have just demolished it without a thought. But if it was a Portico that housed Gods/ess even if its time had passed as a functioning walkway the superstitious Romans aren't about to kick twelve Major Gods/ess to the street and incur their wraith. So *it seems* that the Vespasians built this shrine-like Portico who's only function was to house these Gods and Goddess'? So what you have is just a short dog-legged __/ section of a portico, one source called this new structure "...ungainly makeshift".
This area was first excavated in 1547 but that was just to strip the marble-facing on the brick walls of the lower rooms. In 1832-35 this area was archaeologically excavated and in 1858 the Portico and the rooms were reconstructed. The large capitals of Travertine laying on the ground in front of the Portico are believed to have once been part of the outside upper floor of the Tabularium. Also in the original nineteenth Century excavation they said that fragments of the 'Arch of Tiberius' were also found there? If so I'd be inclined to believe that the Arch was cannibalized to make a later (Medieval?) structure in this location?
Ok let's start with the ROOMS and leave the colonnade for last. Now beneath this structure facing the left side of the Temple of Vespasian and Titus are six brick-faced concrete rooms. And above them behind the colonnade are seven brick-faced concrete rooms. These rooms were small, dark and windowless and we can only guess at their purpose.
Let's start with the six BASEMENT ROOMS: They seem to be small office spaces and Cicero has mentioned the "Clerks of the Clivius Capitolinus" so that's a possibly for them. Another source suggests they were shops of some kind.
The seven ROOMS BEHIND THE COLONNADE: Six rooms are intact but the seventh on the right is missing its roof, its right side and part of the front. Some sources believe there were more rooms (where Vespasian's Temple now is), probably twelve, with one for each God/ess? It's possible that the statues were displayed within the rooms but that seems very odd and irregular to have them out of sight and hidden? A guess? Perhaps they were just individual shrines to each God/ess with the statues in front of them? Some sources think that these were the Clerk Offices while others think that the statues were displayed in pairs in the six intact rooms? But it's very possible they had some other utilitarian purpose completely unrelated to the Portico or Statues?
The rear wall of those rooms on the left is actually a very ancient Tufa retaining wall which supported the Clivius Capitolinus (street).
The GILDED BRONZE STATUES: Most believe were either displayed in-between the columns or on the trapezoidal area that was paved in marble in front of the colonnade. Varro wrote that the statues stood "ad forum" which one source believes meant in that paved area in front of the portico? In my opinion if you want to pair the Gods and Goddess' together and make it a lot more visually striking, putting the statues in the open with the portico as a backdrop seems to be the better option?
The PORTICO: Well we know it was likely built by the Vespasian boys, so 80's AD. Now there was also a major fire in 80 AD that destroyed this area along with a good chunk of Rome. Maybe this is all tied in? The original Portico is destroyed and must be rebuilt so why not put dad's Temple in that burned out space and rebuilt the Gods/ess Portico on a smaller scale next to it?
There were twelve CORINTHIAN COLUMNS made of Carystian/Cipollino green marble from Greece but the five columns on the right are a modern restoration (1858) of White Travertine columns. The original columns on the left are fluted but the modern replacements on the right are unfluted? Also the lower section of the original columns are ornamented with astragals (a beaded decoration). One source claims that the original right-hand columns were unfluted Carystian marble. If so, either there was a reason in the original construction for this difference (perhaps displaying male Gods and female Goddess' on separate sides?). Or it's possible in a later (367 AD?) restoration money was tight and another building or monument was cannibalized (very common in the Late Empire). The original CAPITALS are Corinthian with the sides decorated with reliefs representing trophies.
The ARCHITRAVE INSCRIPTION is a bit historical, in that this was the last Pagan monument restored in Rome. It was restored by 'Vettius Agorius Praetextatus' in 367 AD who was the 'Prefect of the City' (Praefectus Urbi) and is recorded in the inscription. [The inscription reads: deorum cONSENTIUM SACROSANCTA SIMVLACRA CVM OMNI LOci totius adornatioNE CVLTV IN formam antiquam restituto vETTIVS PRAETEXTATVS · V · C · PRAefectus uRBI reposuit CVRANTE LONGEIO . . . . . . . v · c · cONSVLARI]
Praetextatus, his wife and a group of supporters were intellectuals staunchly fighting on in support of Paganism which is rapidly dying out. There are eleven surviving inscriptions of Praetextatus and his wife Paulina like this one penelope.uchicago.edu/Thayer/E/Gazetteer/Places/Europe/Italy/Lazio/Roma/Rome/museums/Museo_Nazionale_Romano/Palazzo_Altemps/inscriptions/Vettius_Praetextatus.html But the most important one was found right here along the Clivus Capitolinus (the street leading up to the Portico). It was his and his wife's long funerary epitaph which was a poem in Iambic Senarii. It was published in 1750. The inscription is now in the Capitoline Muesum. He was one of the last official opponents of Christianity, although he won't live to see it in 394 AD the last Pagan Temple (Vesta - Vestal Virgins) in Rome is closed. The rooms behind the Portico were also restored by him, who knows perhaps *then* he had to put his Gods and Goddess' inside to protect them from those Christians :-) .
For more information and photos, please see Porticus Deorum Consentium in A Tourist in Rome.Next: #12.5: Clivus Capitolinus