In the Cappadocia of the fourth century, Macrina the Younger taught theology to her brothers Basil and Gregory of Nyssa in the household where they had grown up together. With their dear friend Gregory of Nazianzus, whom Basil had known since their student days at Athens, the four of them kept a conversation across decades of letters, sermons, disputes, and love, and out of that conversation came a way of thinking Christianly that carried the inheritance of Greek philosophy inside it.