Summary: This project will be the first project devoted to the study of key Neo-Scholastic authors and their approach to the natural sciences. Even if the Neo-Scholastic movement in the early twentieth century has been the object of some studies (Heynickx and Symons volume, 2018), its approach to the natural sciences has been seldom analysed. In particular, the project will study how scholars within the renaissance of Thomism in the late nineteenth and early twentieth centuries assessed the sciences of origins of the times, namely the theory of evolution of biological species and the nebular hypothesis for explaining the formation of the solar system and galaxies. Thomism saw a revival after the great impulse of Pope Leo XIII’s mandate to study the work of Thomas Aquinas in every Catholic seminary around the globe. His aim in his late-nineteenth-century encyclical Aeterni Patris (1879), was to call all Catholic philosophers and theologians