This thesis offers the first reading of the letters of Catherine the Great as a unified epistolary corpus with literary merit as well as historical value. It explores how the empress employed a key eighteenth-century literary form - the letter - not only to make tactical interventions in political and cultural life, but also to shape her persona. The often contrastive style of her letters balances a charming epistolary voice, suited to the letter as a practice of sociability, with exhibitions of the empress's power and stature as a great individual on the historical stage. The interplay between these two facets, sociability and grandeur, defines her unique approach to the letter form as well as the image of the enlightened monarch as she created it. She displayed her mastery, both literary and political, by creatively manipulating all aspects of the letter, from language choice through etiquette and materiality. Both her lively and seductive personal style and her regal character as an Enlightenment great man derived from and reappropriated available literary models. Seeking to ensure that this image reached receptive audiences, Catherine also carefully controlled the circulation of her letters: in keeping with the semi-privacy of the eighteenth-century letter, she wrote first and foremost to win a reputation with cultural and social elites who exchanged letters out of print. At the same time, she manipulated indirectly through her correspondents the image received by a broader public of her contemporaries and of future generations. The French Revolution challenged all her values, troubling also her elite mode of sociable correspondence and her eighteenth-century version of glory. Yet, to the end of her days Catherine employed her dual style as the best means of writing herself into history.