The Book of Acts places Paul the Apostle in Athens in the middle of the first century CE, disputing daily in the agora and drawing the attention of Epicurean and Stoic philosophers, who brought him before the Areopagus, the ancient council that met on the rocky outcrop below the Acropolis and had once judged homicide and impiety cases in the city's classical period. Paul is said to have opened his address by pointing to an altar he had seen inscribed "to an unknown god," and to have argued from it toward the God of Jewish and Christian monotheism. Acts records a mixed response, mockery from some, curiosity from others, and the conversion of one council member, Dionysius the Areopagite, whose name later attached itself to an influential body of Christian mystical writing composed centuries afterward.
Athens itself Christianized slowly and unevenly. It remained a center of pagan philosophical teaching long after Constantine, home to a Platonic Academy that traced its founding, by reputation, back to Plato himself, until the Christian emperor Justinian closed it in 529 CE as part of a broader suppression of pagan instruction. The city sits some twenty kilometers from Eleusis, whose own Mysteries of Demeter and Persephone were the other great strand of Athenian religious life and continued, protected by imperial tolerance, into the same late fourth century that saw Christianity become the empire's state religion.