After purchasing land located northeast of Forum of Caesar, he ordered the design of a new complex, of which construction was commenced between 30 and 27 B.C It was not completed until 2 A.D. (the Temple of Mars was still unfinished). For this occasion, as chroniclers report games to celebrate this event took place, during which to amuse the Roman populace 260 lions and 36 crocodiles were killed, gladiator fights took place and there was a staging of a naval battle.

Forum Augustum was to have many functions – the principal one was representative and propaganda. In 27 A.D. Octavian was granted the title of Augustus by the Senate, meaning „first among equals”. In this way he became the first Roman emperor. However, he desired to keep up republican appearances, that is why on one hand he showed himself to be a continuator of the tradition of the Republic, while introducing a new theme, which was strictly imperial. He felt himself to be the descendant and successor to the dictator Caesar – a real, although camouflaged sole ruler.

Apart from that the forum was designated for religious, state and judicial purposes. Military councils took place here as well as those regarding the granting of triumphs, here young Romans were taught about their duties before having the honor of putting on a toga, meaning de facto entry into adulthood.

Forum – with the dimensions of 125 by 118 meters – on the north was separated from the so-called Suburra, a densely populated district of the poor, by a wall (in the past 33-meters high) that still stands today. It was an effective barrier not only against the chaotically built, wooden insulae, but also against fires which often broke out there. The main structure of the complex was the temple devoted to Mars the Avenger (Ultor). Its front from the side of the square was adorned by a row of Corinthian columns, on which a high entablature rested, decorated alternatively with figures of free-standing caryatids and medallions with the heads of deities. Inside there was a cell with the statues of Mars, Venus and Cupid. It is here in the niches, that most likely figures of other worshipped deities were placed. In front of the temple a gigantic statue of Augustus himself was erected, standing on a chariot drawn by horses (quadriga), funded by the senators with public money. The inscription upon it relates to his status – father of the fatherland and thus a caring protector. The second inscription enumerated the names of conquered nations, in this way providing evidence of Augustus’s courage and underlining the prosperity which the Roman populace experienced after wars waged by the emperor, in this way accentuating the leading role of Rome in the then world. The reign of Octavian was unequivocally connected with the coming of a golden age. The divine roots of Augustus were also not forgotten, since he belonged to the Julia family, of which the legendary ancestor was Aeneas, the founder of the city (son of Venus). His statue along with those of Romulus and  Remus as well as others of the great forefathers of Romans, among which there were also important figures from the times of the Republic, were placed on either side of the square in a colonnade symmetrically adorned from west and east with exedrae (according to most recent research there were most likely as many as four!).

Subsequent emperors took care to keep the forum in good shape, ordering its conservation. However, in later times it was gradually neglected  and finally the representative square was nothing more than a ruin. In the XVI century during the pontificate of Pope Pius V, its remains were used to build a Dominican convent and a church erected here, while the rest was used as a building material and a street was set out through the forum itself.

It was not until the XIX century, that archeological research was conducted in the area. During the dictatorship of Benito Mussolini, the church as well as other structures built over the ages were torn down, the area of the antique forum was dug up and uncovered, the remains of the temple were secured (three columns of the right colonnade, stairs, podium, and a fragment of the cell) and a footbridge was built which allowed to admire these ancient remains. The excavations concentrated mainly on the north side of the forum, since its southern part was buried, thus creating a location for via dell’Impero (present-day via dei Fori Imperiali), built by Mussolini.