The correspondence between Louis XVI and his foreign secretary the comte de Vergennes represents a major new source for the history of French diplomacy and warfare in the last years of the ancien régime. New light is shed on France’s intervention in the American War of Independence – and in particular on how and why the king’s decision to intervene was taken; on the Franco-Austrian alliance, and the pacte de famille with Spain. But since Vergennes was also from 1783 chef du conseil royal des finances, we learn too about the credit crisis of 1783 and the abortive attempt to end tax-farming, the diamond necklace affair, and the plans for the Assembly of Notables.

Moreover the nearly 200 letters from the king, largely unpublished and still in the possession of the Vergennes family, allow us for the first time to grasp the outlines of the kind’s mind and character, his sense of humour, his turn of phrase. Hitherto fewer than fifty of his letters were known for the period before 1789, many of dubious authenticity. Given Louis’s extreme taciturnity and shyness it is simply not possible to know the man except through his letters. These are more plentiful for for the revolutionary period, but Louis’s character changed at the that time: he became more uxorious, for example, whereas before 1787 he had rigidly excluded Marie-Antoinette from decision-making. In the earlier period, with which this book is concerned, Louis was also harder, more decisive, more on top of his subject – foreign policy – which itself was later displaced as his main concern. 

The letters are set in context throughout, with extracts from the diplomatic despatches which generate most of them, and the foreign policy of the reign up to the Revolution is reassessed in a substantial introductory essay.