Leo XIII and the Development of 20th Century Catholic Theology

This dissertation considers the theological writings of Vincenzo Gioacchino Raffaele Luigi Pecci (1810-1903), better known to history as Pope Leo XIII. During his papacy (1878-1903), Leo began many important new traditions which have had a lasting impact on the development of the Catholic theological tradition. While most scholars tend to focus on Leo’s social teaching, as expressed in his 1891 encyclical Rerum Novarum, I show that Leo made considerable contributions in other key areas. Further, Leo’s papacy represents a critical lynch-pin in the development of the modern Catholic church. In particular, I argue that his call for the revival of Thomas Aquinas as a key theological voice to respond to the challenges of the Enlightenment (Ch. 1), his arguments about the prudential use of the historical critical method of biblical studies (Ch. 2), and his numerous statements on the relationship between the Catholic Church and the modern state (Ch. 3) have all led to lasting and considerable theological developments. By drawing attention to Leo’s work in these areas, I show that he is not merely a figure of history, but one whose teachings and arguments still reverberate within the Catholic church. In addition, by giving a more complex treatment of the context of his writing and the wider scope of his theology, I problematize some of the common characterizations of Leo as a “conservative” pope.