Written by Arrian, a student of Epictetus', the Enchiridion is a book of practical stoic philosophy. Both men were Greeks who lived in Rome, although Epictetus, the senior of the two, lived there in slavery. He developed his philosophical ideas largely after being exiled to Greece. He was an important leader in his day. When Arrian writes this book, he borrows largely from Discourses of Epictetus, but he focuses only upon the more practical quotidian elements of his sage's teachings. His goal appears to be mental health for the readers.
During the Ancient and Medieval periods, Enchiridion was widely circulated and read. People really related to the simple precepts which Arrian lays out in the volume. Monks in Greek monasteries became particularly engaged with the book. Having been translated into multiple languages, the book was printed all throughout Europe after printing was invented. With the rise of the Neostoicist Movement, the teachings of Epictetus became more and more popular.
Enchiridion was published in A.D. 125 in Koine Greek. Written for Greeks, the book was not translated into Latin for sometime, despite its having been written in Rome. As Epictetus' reputation become increasingly contested in Rome leading up to his exile, his writings became more widely circulated. Anyone who could manage to read Greek also owned this volume.