Pseudo-Dionysius the Areopagite in the context of "Pseudepigrapha"

A guardian angel is a type of angel that is assigned to protect and guide a particular person, group or nation. Belief in tutelary beings can be traced throughout all antiquity. The idea of angels that guard over people played a major role in Ancient Judaism. In Christianity, the hierarchy of angels was extensively developed in the 5th century by Pseudo-Dionysius the Areopagite. The theology of angels and tutelary spirits has undergone many changes since the 5th century. The belief is that guardian angels serve to protect whichever person God assigns them to. The Memorial of the Holy Guardian Angels is celebrated on 2 October.

The idea of a guardian angel is central to the 15th-century book The Book of the Sacred Magic of Abramelin the Mage by Abraham of Worms, a German Cabalist. In 1897, this book was translated into English by Samuel Liddell MacGregor Mathers (1854–1918), a co-founder of the Hermetic Order of the Golden Dawn, who styled the guardian angel as the Holy Guardian Angel.

A pseudepigraph (also anglicized as "pseudepigraphon") is a falsely attributed work, a text whose claimed author is not the true author, or a work whose real author attributed it to a figure of the past. The name of the author to whom the work is falsely attributed is often prefixed with the particle "pseudo-", such as "pseudo-Aristotle" or "pseudo-Dionysius." These terms refer to the anonymous authors of works falsely attributed to Aristotle and Dionysius the Areopagite, respectively.

In biblical studies, the term pseudepigrapha can refer to an assorted collection of Jewish religious works thought to be written c. 300 BCE to 300 CE. They are distinguished by Protestants from the deuterocanonical books (Catholic and Orthodox) or Apocrypha (Protestant), the books that appear in extant copies of the Septuagint in the fourth century or later and the Vulgate, but not in the Hebrew Bible or in Protestant Bibles. In Catholic usage, the Old Testament books accepted by the Catholic Church are referred to as the deuterocanonical books, and Catholic writers commonly reserve the word apocrypha for spurious or noncanonical writings rather than for the deuterocanon. In addition, two books considered canonical in the Orthodox Tewahedo churches, the Book of Enoch and Book of Jubilees, are noncanonical in Catholic and Eastern Orthodox canons and are classified by most scholars among the Old Testament pseudepigrapha.

The hierarchy of the Catholic Church consists of its bishops, priests, and deacons. In the ecclesiological sense of the term, "hierarchy" strictly means the "holy ordering" of the church, the Body of Christ, so to respect the diversity of gifts and ministries necessary for genuine unity.

In canonical and general usage, it refers to those who exercise authority within a Christian church. In the Catholic Church, authority rests chiefly with bishops, while priests and deacons serve as their assistants, co-workers or helpers. Accordingly, "hierarchy of the Catholic Church" is also used to refer to the bishops alone. The term "pope" was still used loosely until the sixth century, being at times assumed by other bishops. The term "hierarchy" became popular only in the sixth century, due to the writings of Pseudo-Dionysius.

In Christianity, the Devil, also known as Satan, is a malevolent entity that deceives and tempts humans. Frequently viewed as the personification of evil, he is traditionally held to have rebelled against God in an attempt to become equal to God himself. He is said to be a fallen angel, who was expelled from Heaven at the beginning of time, before God created the material world, and is in constant opposition to God. The Devil is identified with several other figures in the Bible including Lucifer, Satan, the serpent in the Garden of Eden, the tempter of the Gospels, Leviathan, Beelzebub, and the dragon in the Book of Revelation.

Early scholars discussed the role of the Devil. Scholars influenced by neoplatonic cosmology, like Origen and Pseudo-Dionysius, portrayed the Devil as representing deficiency and emptiness, the entity most remote from the divine. According to Augustine of Hippo, the realm of the Devil is not nothingness, but an inferior realm standing in opposition to God. The standard medieval depiction of the Devil goes back to Gregory the Great. He integrated the Devil, as the first creation of God, into the Christian angelic hierarchy as the highest of the angels (either a cherub or a seraph) who fell far, into the depths of hell, and became the leader of demons.

Neoplatonism was a major influence on Christian theology throughout Late Antiquity and the Middle Ages in the East, and sometimes in the West as well. In the East, major Greek Fathers like Basil, Gregory of Nyssa and Gregory of Nazianzus were influenced by Platonism and Neoplatonism, but also Stoicism often leading towards asceticism and harsh treatment of the body, for example stylite asceticism. In the West, St. Augustine of Hippo was influenced by the early Neoplatonists Plotinus and Porphyry. Later on, in the East, the works of the Christian writer Pseudo-Dionysius the Areopagite, who was influenced by later Neoplatonists such as Proclus and Damascius, became a critical work on which Greek church fathers based their theology, like Maximus believing it was an original work of Dionysius the Areopagite.

The Enneads (/ˈɛniædz/; Ancient Greek: Ἐννεάδες), fully The Six Enneads, is the collection of writings of the philosopher Plotinus, edited and compiled by his student Porphyry (c. AD 270). Plotinus was a student of Ammonius Saccas, and together they were founders of Neoplatonism. His work, through Augustine of Hippo, the Cappadocian Fathers, Pseudo-Dionysius the Areopagite and several subsequent Christian and Muslim thinkers, has greatly influenced Western and Near-Eastern thought.