Pseudo-Dionysius the Areopagite, a pseudonymous author of the early Christian period, emerged as a significant and enigmatic figure in the development of Christian mystical and Neoplatonic thought. His collected works, collectively known as the 'Corpus Dionysiacum,' profoundly shaped the theological and philosophical landscape of the Middle Ages and beyond. Although his true identity remains shrouded in mystery, Pseudo-Dionysius is traditionally associated with the figure of St. Paul's Athenian convert, Dionysius the Areopagite, mentioned in the Acts of the Apostles (Acts 17:34). However, modern scholarship places the authorship of his texts much later, around the end of the 5th or early 6th century, attributed to his synthesis of Patristic and Neoplatonic ideas, which were well developed by this time. Among his extant works, the 'Ecclesiastical Hierarchy' is a central treatise that expounds on the angelic and ecclesiastical orders, reflecting the mystical theology through which one could achieve union with God through participation in the Church's sacraments and hierarchy. Pseudo-Dionysius' literary style combines intricate allegory and symbolic theology, characterized by a transcendent and apophatic approach to God, which means that he stressed the ineffability of the divine essence and the limitations of human language in describing the divine. His works, including 'The Divine Names,' 'The Mystical Theology,' and the 'Celestial Hierarchy,' remain foundational texts within both Eastern Orthodox and Western Christian mystical tradition.