See this legally free ebook:
- The Life of the Blessed Emperor Constantine, by Eusebius Pamphilius (London: Samuel Bagsters and Sons, 1845). With the Oration of the Emperor Constantine which He Addressed “To the Assembly of Saints”; and the Oration of Eusebius Pamphilius in Praise of the Emperor Constantine. May be read online, and available in pdf, mobi, and epub formats, at Internet Archive.
On the Sunday of the Fathers at the First Ecumenical Council, and on the Feasts of Saint Constantine the Great and Saint Helena, in the Eastern Catholic Churches. For other texts and ebooks, you may access the List of Free eBooks (Arranged by Title), the List of Free eBooks (Grouped by Subject), the List of Worth-It Catholic Books & eBooks, and the main page of the Catholic eBooks Project.