On the two long sides the square of the Forum of Augustus was flanked by porticoes. The façade was decorated with fluted Corinthian columns made of Giallo Antico marble (coming from the modern day Tunisia). The columns supported an attic decorated with Caryatids modeled on those from the Erechtheum in Athens and alternating with large marble shields bearing heads of deities in the centre. The porticoes floors displayed rich colored marble patterns and each of them opened up to a pair of hemicycles with a diameter of 40 meters.
The western pair of hemicycles were demolished during the construction of the Forum of Nerva (97 A.D.) and the Forum of Trajan (112-113 A.D.) so that the porticoes in the Forum of Augustus were left with only one hemicycle each. These spaces were furnished with a gallery of statues portraying famous men of Rome (summi viri) as well as members of the Iulia dynasty to which Augustus himself belonged. Trials would be held inside the hemicycles by the ancient Roman judges (praetores). In the northern hemicycle (below you) the praetor urbanus would preside over lawsuits involving Roman citizens while in the opposite hemicycle (south) the praetor peregrinus would take care of legal matters involving foreigners (peregrini) who did not have the Roman citizenship.
The northern portico ended in a lavishly decorated room, the so-called “Hall of the Colossus” (in front of you). A colossal statue of Augustus (between 11 and 12 meters tall) was placed on a base in this hall as a symbol of the equality of justice administered by the judges in the nearby tribunals. In the Museum of the Imperial Fora you can see many marble fragments from this part of the Forum of Augustus.