Aeterni Patris is Leo XIII's second encyclical letter, published the second year of his pontificate. For a historical context of the 1870s click here. For some background about the encyclical click here.
As a curiosity, click here to see a short video of Leo XIII, the first pope to be filmed. Aeterni Patris is the first papal document in modern times to focus exclusively on the place of philosophy in Catholic life. This is its most remarkable aspect. The mention of St Thomas Aquinas as a point of reference must be seen within this context. Among others including St Augustine and other Fathers of the Church, St Thomas is an outstanding point of reference on the right and smart exercise of philosophy in its three functions: as a preparation for the receiving of faith; as a technical support for the development of theology; and as tool in apologetics.
Through Pope Leo XIII's encyclical, the Church invites us to consider this challenge:
Those, therefore, who to the study of philosophy unite obedience to the Christian faith, are philosophizing in the best possible way...For surely that is a worthy and most useful exercise of reason when men give their minds to disproving those things which are repugnant to faith and proving the things which conform to faith... (Aeterni Patris 9).