See this legally free ebook:
- The Purpose of the Papacy, by Bishop John S. Vaughan (London: Sands & Co.; St. Louis, Mo., U.S.A.: B. Herder, 1910). Available in various formats at Project Gutenberg, ManyBooks.net, and Internet Archive.
On the Memorial of Pope St. Gregory the Great in the Ordinary Form of the Roman Rite, and the Feast of Pope St. Pius X in the Extraordinary Form of the Roman Rite. For more legally free ebooks, you may access the List of Free eBooks (Arranged by Title) and the List of Free eBooks (Grouped by Subject). Blessed be God in His angels and in His saints!