Origen, or Origen Adamantius (184/185 - 253/254), was a scholar, early Christian theologian and Church Father, who was born and spent the first half of his career in Alexandria. He was a prolific writer in multiple branches of theology, including textual criticism, biblical exegesis and hermeneutics, philosophical theology, preaching, and spirituality. Some of his reputed teachings, such as the pre-existence of souls, the final reconciliation of all creatures, including perhaps even the devil (the apokatastasis), and the subordination of the Son of God to God the Father, later became controversial among Christian theologians. A later group of Egyptian monks who came to be known as Origenists, and who believed in the preexistence of souls and the apokatastasis, were declared anathema in 553 AD. This condemnation is attributed to the Second Ecumenical Council of Constantinople, though it does not appear in the council's official minutes. For this reason Origen was and is not called a "saint" in either the Catholic or Orthodox churches.

Quintus Tertullian (c. 160-c. 220) is distinguished by being the first major Christian thinker to write in the Latin language. According to Eusebius, he was raised in Carthage, the son of a Roman centurion. Following his conversion to the faith, he became an impassioned defender of the rights of Christians. Origen Adamantius (c. 185-254) taught in Alexandria, reviving the catechetical school of Alexandria in which Clement of Alexandria had taught. His translations, commentaries, and theological works mark him as one of the finest minds of early Christianity. John Cassian (c. 360-435), born in Europe, first joined a monastery in Palestine and then traveled to Egypt to learn from the Desert Fathers. After his return to Europe, he founded a monastery in southern France. His writings would eventually influence St. Benedict, who recommended Cassian's texts to his monks. All three writers in this collection offer reflections on the Lord's Prayer, together with practical advice for prayer. This common ground provides a basis for comparisons, along with a rich picture of Christian spirituality in the ancient world. At the same time, the authors address questions about prayer that are still relevant today.