So densely crowded were the historical buildings and remarkable sites in that part of the Forum which lay immediately behind the Capitol, that it is almost impossible now to identify their position or remains.  This spot forms the great battle-ground of the antiquaries, whose conclusions in many instances are mere guess-work.  Below the medieval tower of the Capitol is a wide space paved with fragments of coloured marbles, and with indications of the ground-plan of a building.  This is supposed to mark the site of the Temple of Concord, erected by the great general Camillus, after the expulsion of the Gauls, to perpetuate the concord between the plebeians and patricians on the vexed question of the election of consuls.  It was placed beside the old meeting-place of the privileged families.  From the charred state of some of its sculptures discovered on the spot, it is supposed to have been destroyed by fire.  It was restored and enlarged a hundred and twenty years before Christ by the Consul Opimius immediately after the murder of Caius Gracchus.  To the classical student it is specially interesting as the place where Cicero convoked the senate after the discovery of the Catiline conspiracy, for the purpose of fixing the punishment due to one of the greatest of crimes.  Among the senators present on that memorable occasion were men of the highest political and philosophical renown, including Caesar, Cato, and Cicero.  They came to the conclusion that there was no such thing as retribution beyond the grave, no future state of consciousness, no immortality of the soul; consequently death was considered too mild a punishment for the impious treason of the conspirators; and a penalty, which should keep alive instead of extinguishing suffering, was advocated.  We learn from this extraordinary argument, as Merivale well says, how utter was the religious scepticism among the brightest intellects of Rome only thirty-seven years before the coming of Christ.  The very name of the temple itself, dedicated not to a divine being as in a more pious age, but to a mere political abstraction, a mere symbol of a compact effected between two discordant parties in the state, indicated how greatly the Romans had declined from their primitive faith.

But the most conspicuous of the ancient remains in this quarter, and the first to attract the notice of every visitor, is the Ionic portico of eight columns, called at first the Temple of Jupiter, and then of Vespasian, but now definitely determined to be the Temple of Saturn, for it is closely connected with the AErarium, and the AErarium is said by several ancient authors to have led into the podium of the temple by a doorway in its wall still visible.  This temple is supposed to be of very early origin, and to have marked the site of an ancient Sabine altar to the oldest of the gods of Italy long before the arrival of the Romans.  It was nearly entire so late as the fifteenth century; but its cella was ruthlessly destroyed shortly afterwards, and its marble ornaments used for making lime.  The present group of pillars was so clumsily restored by the French at the beginning of this century that they are seen to differ from each other in diameter, and the frieze is composed of fragments that do not harmonise.