Voltaire’s historical writings form a significant part of his output, including works on Louis XIV, Louis XV, Charles XII, Peter the Great, the Holy Roman Empire, and even a pioneering universal history. These histories were highly regarded in his lifetime, and Voltaire was a powerful influence on the other great historians of the age, Hume, Gibbon and Robertson.
Despite this, writers now are uncomfortable in trying to explain the importance of Voltaire as a historian. Karen O’Brien, for example, remarks that ‘Voltaire’s histories have not recovered today from the low reputation to which they sank after the French Revolution’.  We typically criticise Voltaire’s histories for being polemical and tendentious: his determination to view everything from a resolutely modern point of view can make him seem naïve, and some find it puzzling that his histories were once held in such esteem.
The aim of the Voltaire: historian of modernity project is to come to a better understanding of Voltaire’s overall philosophical project, by focusing on a neglected aspect of his work: his determination to write ‘modern’ history. Much of his historical writing, especially in the earlier years, is devoted to the modern world. Voltaire first explores the defining characteristics of the modern world (the benefits of trade, the scientific revolution, religious toleration) in a book about England (Lettres sur les Anglais, or Lettres philosophiques), before studying the flourishing culture of France during the previous century (Le Siècle de Louis XIV). He then extends this exploration, forwards into modern France (Précis du siècle de Louis XV), and outwards into the recent history of the whole world (Essai sur les mœurs).
The study of recent history was, Voltaire declared bluntly, ‘a matter of necessity’.  The study of modern times was more precise than the study of ancient history, because sources were more numerous and more reliable. Most importantly – and here Voltaire seems influenced by the English writer Bolingbroke – modern history is best placed to offer us instructive examples. Traditionally, it had always been ancient history that was thought to be significant as a source of morally improving examples of conduct. Voltaire turns that idea on its head. As an Enlightenment philosopher, he wants to teach the lessons of free thought and religious tolerance, and he turns to modern history for telling examples to prove his point.
Voltaire’s histories are not in a separate category on the margins of his œuvre: they are at its very core. We need to (re)read the modern histories alongside Voltaire’s other polemical works, and to understand them as part of one and the same project. The spirit of criticism that characterises the Enlightenment begins when we scrutinise our own age, and we cannot fully understand Voltaire the philosopher without appreciating his commitment to the study of modern history. 
– Nicholas Cronk
 Narratives of Enlightenment: cosmopolitan history from Voltaire to Gibbon (Cambridge, 1997), p.21.
 Conseils à un journaliste, see Œuvres complètes de Voltaire, vol.20A (Oxford, Voltaire Foundation, 2003), p.482.
 This blog post is based on an article that first appeared in the Leverhulme Trust Newsletter in 2014.