The Imperial Fora were very important public and ceremonial areas in Rome. These areas had practical use, especially when the population of Rome began to grow rapidly. They also provided more room for government, business, religious worship, and gave the Emperors both notoriety and immortality.
The Forum Iulium (Forum of Julius Caesar) was the first of the Imperial Fora to be built. Julius Caesar himself began planning it in 54 BCE, probably to rival nemesis Pompey's large theater complex. Using the spoils of his campaigns and victory in Gaul, he designed a forum that would serve not as a marketplace, but as an area to accommodate Rome's other business and governmental interests. Rome's growing population was also putting a squeeze on the Forum Romanum, and this new space was much needed. Caesar's forum was officially dedicated in 46 BCE, though it was unfinished. The Forum Iulium was completed some time after Caesar's assassination by Augustus.
The template of this forum is one by which the other fora followed closely. It was rectangular, approximately 115 x 30 meters, with a colonnade surrounding it. At the end of this forum was the Temple of Venus Genetrix (Venus the Universal Mother of the Roman people).
Forum of Augustus
The second Imperial forum built in Rome was the Forum of Augustus. Built both to rival the Forum Iulium and to accommodate even more growth in Rome's population, this forum was begun around 20 BCE, using the spoils of battles fought against Spain, Germany, and Egypt.
The Forum of Augustus was built adjacent to Caesar's Forum, and it allowed more space for the law courts and other government functions. Though not all of the land required to complete the original plan could be purchased, construction of the forum and its centerpiece, the Temple of Mars Ultor (the Avenger), went ahead. The unfinished forum was dedicated in 2 BCE, with elements added by Tiberius (two arches) in 19 CE, and restorations carried out by Hadrian.
The Forum of Vespasian was dominated by the Temple of Peace, and the area is sometimes referred to by that name. After emperor Vespasian captured Jerusalem in 71 CE, he began plans for this area. The forum also contained two long halls that likely were Greek and Latin libraries. The Forum of Vespasian was meant to commemorate the end of the Jewish was and signal the beginning of a period of long-sought peace in Rome. The Temple of Peace, revered for its size and grandeur, and the forum were dedicated in 75 CE.
The Forum of Nerva was begun by Domitian and completed by Nerva in 97 CE. It is also known as the Forum Transitorium, because of the way it enclosed the Argiletum (a street in the city that led to residential areas), which was a main throughway between the Subura (a less desirable and densely populated district in the city) and the Forum Romanum. This forum included a temple to Minerva and a temple to Janus (a two-headed god of doors, beginnings, and endings).
The largest and most impressive of the Imperial Fora was also the last one in Rome, the Forum of Trajan. This forum was dedicated in 112 CE. It had originally been started by Domitian, but work ceased with his assassination in 96 CE. When Trajan saw victory in Dacia in 107 CE, he used the spoils to complete the forum. The forum held several different structures, with varying functions. These included a true forum area, a colonnaded public square (a piazza). There was also the Basilica Ulpia, libraries, the Column of Trajan, and the Markets of Trajan. It was in this forum that the consuls held office and slaves were freed (manumitted). After Trajan's death, Hadrian had the Temple of Divine Trajan built there.