 The important question concerning any statement contained in an historical source “is not whether it is true or false, but what it means” (IH 1993: 260). Ignoring this advice leads to writing “scissors-and-paste” histories where the sources are treated as worthwhile historical material and admitted into the historian’s narrative only if they are deemed to be believable by the historian’s own standards of evidence. To understand the past historically is to understand the “context of thought” (IH 1993: 299) of past agents, their frame of mind. What makes an investigation historical, therefore, is not simply the fact that it is focused on the past, but the kind of concerns by which it is guided when investigating the past. To understand past agents is to understand the way in which they reasoned, the inferences that they drew, the conceptual connections which they made, the symbolic significance they attached to certain events. Understanding a past occurrence, such as Caesar’s crossing of the Rubicon historically, for example, is to understand the significance that it had for a contemporary Roman who knew what Roman law permitted and proscribed. This is what differentiates a concern with the historical past from a concern with the natural past: