The Temple of Saturn is the oldest sacred place in Rome, after the Temples of Vesta and Jupiter. The present ruins represent the third phase of the Temple of Saturn, which was built in 360 CE after a previous fire. The temple was situated in front of an important open square or area, where a number of other notable structures were located, including the Arch of Septimius Severus, Umbilicus urbis Romae (naval of the city of Rome), area Volcani,

In Roman mythology, Saturn ruled during the Golden Age, and he continued to be associated with wealth. His temple housed the treasury, the aerarium, where the Roman Republic's reserves of gold and silver were stored. The state archives and the insignia and official scale for the weighing of metals were also housed there. Later, the aerarium was moved to another building, and the archives transferred to the nearby Tabularium.

Surrounding the Temple of Saturn in the Roman Forum, were a number of notable structures, including Vicus Jugarius, Clivus Capitolinus, Basilica Julia, Temple of Vespasian and Titus, Temple of Concordia, Arch of Tiberius, Tabularium, Arch of Septimius Severus, Umbilicus Urbis Romae, Rostra, and Via Sacra etc.

circa 500 BCE-

Roman Kingdom
An altar of Saturn, which stood somewhere in the area in front of the temple, is thought to have been much older, and was associated with the myth of Saturn's founding of the city on Capitoline Hill. The first, simpler, temple to Saturn is thought to have been first installed on the site during the early period of the Roman Kingdom. Macrobius, writing in circa 400 CE, relates another tradition that Tullus Hostilius, the second king of Rome, dedicated a "fanum shrine" (a piece of ground upon which an aedes was afterwards built), possibly on the same site, to Saturn as a victory monument following his third triumph, over the Sabines, and then instituted the Saturnalia.

Subsequently, under Tarquinius Superbus, the legendary seventh and final king of Rome, a new temple was dedicated and the construction began on a majestic building but was not completed until the early years of Roman Republic. The dynastic struggle during the later years of the fifth century BCE (circa 509-501 BCE) may have played some role in delaying the construction. Around the same time the public treasury, the aerarium, was installed in the temple. Plutarch relates a tradition, during his day, regarding the estanblishment of the aerarium to P. Valerius Poplicola, one of four Roman aristocrats who led the overthrow of the monarchy and became a Roman consul.

Roman Republic
However, its completion and inauguration by the consul Titus Larcius took place in the early years of the Republic (circa 500 BCE), making it the oldest Republican temple after the Temple of Jupiter Optimus Maximus located on the Capitoline Hill. Subsequently the temple of Saturn was completely reconstructed by Munatius Plancus, the consul of Rome, in 42 BCE. Suetonius in his book Life of Augustus (XXIX. 4-5), mentions that the reconstruction of the temple was undertaken by Lucius Munatius Plancus, at the encouragement of Augustus, who "often urged other prominent men to adorn the city with new monuments or to restore and embellish old ones, each according to his means". Plancus is known to have paid for the rebuilding of the temple from his spoils of campaigns against the Rhaetians.

Roman Empire
Although the cult of Saturn persisted and prospered during the Roman Empire until the early third century CE, it is likely that the temple would have been closed during the persecution of pagans which started during the reign of Constantine after the empire's conversion to Christianity.

The temple, however, was again rebuilt in the fourth century CE (circa 360 CE), by the "senate and people of Rome", as recorded on the architrave. The present ruins, comparising of surviving Ionic columns, with their scrolled volutes, date from this reconstruction. This late 4th century CE rebuilding reflects pagan revivalism during this time period.

circa 1200 BCE

Altar
The altar of Saturn, existed before the first temple of Saturn was ever constructed. The altar, according to some traditions, was believed to have predated the temple by at least 600-700 years, possibly from a time before the Trojan War (Festus 430-432). A carved tuffa stone "shrine" has been identified as the "altar of Saturn", situated immediately west of the Arch of Septimius Severus and the Umbilicus Urbis Romae. If this is not the altar of Saturn It is most likely that the remains of the altar are still buried under the modern day Via del Foro Romano.

circa 360 CE

Facade
The pediment and eight surviving columns represent one of the iconic images of Rome's ancient architectural heritage. There are slight differences in height in the shafts of the columns, and the diagonal Ionic capitals have been cut to compensate for this. Except for the unfluted Ionic columns capitals carved in the Late Antique style, all of the materials remaining were taken from other buildings. Examples of the spolia used to construct the Temple of Saturn include Egyptian granite column shafts and a late Republican acanthus frieze. Macrobius mentions the existance of acroteria of Tritons blowing conch shells, like those adorning the altar of Zeus at ancient Pergamum.

circa 360 CE

Podium
The podium, on which the temple remains rest most likely dates back to the Plancus' reconstruction, measures 22.5 meters by 40 meters. It is distinctly higher as compared to the Temple of the Discouri, standing at 9 meters in height. these dimensions would have given the temple a long and narrow appearance, though not excessively so.

circa 360 CE

Architrave
The inscription on the frieze commemorates the restoration of the temple undertaken after a fire. The fire mentioned in the architrave incription is generally believed to be the great fire during the reign of emperor Carinus. The external architrave or the pediment bears the inscription "Senatus Populusque Romanus" and "incendio consumptum restituit", displayed in two lines, meaning "The Senate and People of Rome restored [the temple] consumed by fire.