Tradition says that the first Temple of Castor was vowed by the Romans in 496 in return for his aid and that of his brother Pollux at the Battle of Lake Regillus, and that it was built in 484 B.C. The existing columns probably belong to the rebuilding by Tiberius in A.D. 6, forty-nine years after Cicero's death. Following their pattern of associating temples and state offices, the Romans housed the imperial bureau of weights and measures in this temple's high foundations, open now to public gaze. When the temple fell, no one knows; by the fifteenth century evidently only these columns were standing, for a nearby street was called after them the 'Street of the Three Columns'. In the seventeenth, eighteenth, and much of the nineteenth century they were believed to belong to the Temple of Jupiter Stator, the Steadier, who rallied the wavering Romans in the war which followed the rape of the Sabine women.
Another landmark of the Forum today is the round Temple of Vesta, east of the Temple of Castor. Unseen for centuries, but now partially restored, it was probably lying buried beneath heaped earth when Van Heemskerck made his panoramic drawing of the Forum. This was one of Rome's most venerable shrines. Here burned the perpetual fire sacred to Vesta, guardian of the hearth, tended by the Vestal Virgins, the most severely disciplined, the most privileged, and the most highly honoured among Roman women. Here, too, was kept the Palladium, the image of Pallas Athena fallen from heaven, which Aeneas was said to have brought from burning Troy and passed on to his descendants, the founders of Rome.
In shape the temple followed the pattern of some far older and more primitive shrine, as Ovid stated clearly in his Fasti two thousand years ago: 'The buildings which now you see roofed with bronze you might then have seen roofed with thatch, and the walls were woven of tough willows. . . . Yet the shape of the temple, as it now exists, is said to have been its shape of old, and it is based on a sound reason. Vesta is the same as the Earth; under both of them is a perpetual fire.' Plutarch, a little later, took issue with this philosophy and explained that the temple was built, 'not in imitation of the shape of the earth . . . but of the entire universe, at the centre of which the Pythagoreans place the element of fire.' Actually its shape probably followed the tradition of the primitive Romans' round huts, like the little thatched house so long cherished on the Palatine as the home of Romulus.
However the shape be explained, the temple was unique in containing no statue of its goddess, which may have been kept in a small shrine nearby. It was not, indeed, a regularly consecrated temple, and was guarded by a taboo so strict that no man except the Pontifex Maximus was allowed to enter, and women only during the June festival of the goddess.
The temple was closed by imperial decree in 394 and the remaining Vestals were driven from their house, the near-by Atrium Vestae. When the temple fell into ruin is unknown. The twelfth century knew it in some form, for the Mirabilia, in describing the Forum, states: 'There is the temple of Vesta, where it is said that a dragon coucheth below, as we read in the life of Saint Silvester.' This was the correct location, for it placed the temple near the church of Santa Maria Liberatrice, associated with the story of the dragon. Before 1489 the ruins had evidently been buried for some time, as there is mention of their discovery in that year. Sixty years later, in 1549, they were rediscovered, still fairly complete, and then burned for lime or used by the builders of Saint Peter's. After this the temple's very site seems to have become uncertain, though its shape, described by so many Latin authors, was remembered and its name given to round buildings still standing, such as the little circular temple by the Tiber, which has been called by so many names. The foundations and scattered fragments of the temple in the Forum were again discovered in the 1870's and 80's, and in the 1930's the building was partially reconstructed from pictures on coins and from a relief in the Uffizi. The fragments which remain belong to the reconstruction by the wife of Septimius Severus after the fire of A.D. 191.
The sites of the temples of Vesta and of Castor have been closely coupled since very ancient times. The story of the founding of Castor's temple was old when Dionysius of Halicarnassus retold it in the first century before Christ. At the battle of Lake Regillus, wrote Dionysius, after the Romans had implored the help of the Twin Brothers, Castor and Pollux, there appeared 'two men on horseback, far excelling in both beauty and stature those our human stock produces.' Encouraged by this omen the Romans rallied to victory. 'In the late afternoon, two youths are said to have appeared in the same manner in the Roman Forum attired in military garb, very tall and beautiful and of the same age, themselves retaining on their countenances . . . the look of combatants, and the horses they led being all in a sweat. And when they had each of them watered their horses and washed them at the fountain which rises near the temple of Vesta . . . they related how the battle had gone and that the Romans were the victors. And it is said that after they left the Forum they were not seen again by anyone, though great search was made for them.' Convinced that these were Castor and Pollux, the fabulously skilled horsemen whose aid the army had besought, the Romans built them a temple close by the place where they had watered their steeds.
Two thousand years after Dionysius' day, Macaulay Lays of Ancient Rome put the name of Vesta on every school-child's lips:
'And on rode these strange horsemen,
With slow and lordly pace;
And none who saw their bearing
Durst ask their name or race.
On rode they to the Forum,
While laurel-boughs and flowers
From house-tops and from windows,
Fell on their crests in showers.
When they drew nigh to Vesta,
They vaulted down amain,
And washed their horses in the well
That springs by Vesta's fane.
And straight again they mounted,
And rode to Vesta's door;
Then, like a blast, away they passed,
And no man saw them more.'
The 'well that springs by Vesta's fane' was the fountain of Juturna, nymph of healing waters, still fed by springs from the foot of the Palatine.
Westward from Vesta's temple the triumphal Arch of Septimius Severus closes the end of the Forum. Outstanding as the columns of the ancient temples are, the most impressive monuments of the Forum are this arch and that of Titus just beyond its eastern boundary. These two arches and the Temple of Antoninus and Faustina are the only monuments of this area which have kept their ancient names throughout the centuries, for these alone have retained their inscriptions unburied and readable.
The Arch of Severus was erected by the Senate in A.D. 203 to commemorate the emperor's successful wars against the Parthians and Arabs and it is decorated with scenes from these campaigns. Originally its inscription bore the names of the emperor's two sons, Geta and Caracalla, as well. Later, when Caracalla had his brother murdered, he removed Geta's name and filled the vacant spaces with additional titles for his father and himself. Today the ancient bronze letters are gone, but their matrices and rivet holes still show the wording of both the original inscription and the changes, testifying mutely to a murder seventeen centuries ago. During the Middle Ages the arch was divided between two owners. The church of Saints Sergius and Bacchus held the southern part; the northern was used by a noble Roman family as part of a fortress, one of whose towers still appears in Du Pérac's etching.
Between the Arch of Severus and the Tabularium is the concrete core of the platform on which once stood the Temple of Concord. Nothing else remains of this building in which the Senate met so often except a few architectural fragments, most of which are kept in the Tabularium.
At right angles to the Arch of Severus, on what was once the ancient Comitium or open space for public assemblies, stands the double church dedicated to Saint Martina, a virgin martyr, and Saint Luke, Evangelist and patron of painters. It was founded in honour of Saint Martina in the seventh century, among the ruins of an annex to the Senate House, the Secretarium Senatus; an upper church was added in 1640 and dedicated to their patron Luke by the artists of Rome. Church and triumphal arch together suggest the essential harmony of baroque and imperial Roman styles, with their marriage of column, dome, and arch, their balance of the horizontal and the vertical, and their delight in ornament. The Middle Ages had reared few magnificent structures in the Eternal City, in comparison with the cathedrals and guild halls of northern lands, and much of what was built then in Rome was destroyed by the architects of later times. The Rome of the popes was a baroque city, gorgeous and dramatic, in which emperors of ancient Rome would assuredly have felt at home.
Beside this lavishly decorated church the severely plain Senate House of yellowish brick stands in sharp contrast. Yet no sumptuous monument touches the imagination more deeply than this building, small and now so unadorned.