Gregory of Nyssa recalls a remarkable change in his correspondent: once deeply unbelieving, the man has now become outstanding in faith, a transformation Gregory attributes to divine guidance working through the wise elder Eusebius. Following this conversion, a discussion on fate arose between Gregory and a philosopher in Constantinople. At the request of his now-faithful friend-whom he addresses with deep respect-Gregory agrees to recount that conversation in writing. He emphasizes that his account will be brief, simple, and suitable for a letter, not expanding into a full-length theological treatise
