This article addresses the problem of veracity in ancient historiography. It contests some recent views that the criteria of truth in historical writing were comparable to the standards of forensic rhetoric. Against this I contend that the historians of antiquity did follow their sources with commendable fidelity, superimposing a layer of comment but not adding independent material. To illustrate the point I examine the techniques of the Alexander historian, Q. Curtius Rufus, comparing his treatment of events with a range of other sources that reflect the same tradition. The results can be paralleled in early modern historiography, in the dispute between J. G. Droysen and K. W. Krüger on the character of Callisthenes of Olynthus. Both operate with the same material, but give it different "spins" according to their political perspectives. There is error and hyperbole, but no deliberate fiction.