We at last approach the text of the Decline and Fall, after a sesquimillennial journey from the construction of the Tacitean narrative which is one of the explanatory foundations of Gibbon's first volume. The history of that narrative, traceable as far back before Tacitus as Polybius, is that of a possibly insoluble problem in the relations between libertas and imperium. Liberty achieves empire, but is corrupted by it, and empire cannot be retained once it has destroyed the liberty that once conquered and no longer defends it; yet this self-destructive libertas remains intensely admired, under the name of virtus, as one of the highest achievements of human nature. It is possible to see Athenian philosophy, perhaps as Latinised by Cicero, as a criticism of virtue in this warrior and combative form; but the Athenian ‘empire’ was transitory in comparison with the Roman, and never became a transformation of provinces into a shared ecumenical culture. The problem of libertas et imperium is therefore carried on in the history of Latin historiography rather than Greek philosophy, and the criticism of both virtus and history is achieved by Augustine, who presents both as the work of the libido dominandi, and the civitas dei as the alternative to history.