AbstractThis paper examines Frank Ankersmit as a rationalist. I argue that there is a theory of rationality in Ankersmit, and that rationalism is an essential feature of his philosophy of history. It is salient that, according to Ankersmit, this theory of rationality can be discovered by a priori reasoning through analysing what the concept of representation entails. Ankersmit’s view is that Leibniz has best succeeded in defining what representation is. Further, Leibniz’s theory of representation, and the idea of rationality it entails, are understood to be applicable to history writing, too. The most important standard of rationality is scope. The historian is expected to maximize the scope of her representation, or to create a maximum distance between narrative statements and a narration. The attempts to maximize scope are hampered by other values which stand in opposition to it. For this reason, the historian has to, in effect, find the best possible compromises between two opposing forces – including as much diversity while maintaining as much order as possible, for example. However, no a priori reasoning, or philosophers at large, can in practice determine the most rational representation. This is achieved through historiographical debate and discourse by comparing one representation to its rivals. In the end, I pose some questions and challenges to Ankersmit’s theory of rationality.