“Aeterni patris” encyclical of pope Leo XIII (preface to the publication and translation)

The encyclical of Pope Leo XIII entitled “Aeterni Patris” is an official document of the Roman Catholic Church and expresses the position of the Pope as the Head of the Church in relation to theology, science, and philosophy. In this document, the pope cites the statements of the Holy Fathers and Doctors of the Church in favor of true knowledge, and also gives an example of how these ascetics struggled with errors and delusions. As a top master of theology, philosophy and apologetics, the Pope considers the “angelic doctor” of the Catholic Church i. e. Thomas Aquinas, who put a lot of work in favor of the development of true Christian knowledge. The Pope calls on monastic orders, educational institutions to take the course of following Thomas Aquinas, which will save them from mistakes and allow them to stick to the truth. The significance of this encyclical lies in the fact that it gave rise to a new trend in Catholic theology and philosophy or neo-Thomism, which follows Thomas Aquinas in its method and in its main points. The encyclical may also be useful for studying the history of Western confessions and comparative theology.