Marius, a sensitive only child of a patrician family, growing up near Luna in rural Etruria, is impressed by the traditions and rituals of the ancestral religion of the Lares, by his natural surroundings, and by a boyhood visit to a sanctuary of Aesculapius. His childhood ends with the death of his mother (he had early lost his father) and with his departure for boarding school in Pisae. As a youth he is befriended by and falls under the influence of a brilliant, hedonistic older boy, Flavianus, who awakens in him a love of literature (the two read with delight the story of Cupid and Psyche in Apuleius, and Pater in due course makes Flavian, who is "an ardent student of words, of the literary art", the author of the Pervigilium Veneris). Flavian falls ill during the Festival of Isis and Marius tends him during his long death-agony (end of 'Part the First'). Grown to manhood, Marius now embraces the philosophy of the 'flux' of Heraclitus and the Epicureanism (or Cyrenaicism) of Aristippus. He journeys to Rome (166 AD), encountering by chance on the way a blithesome young knight, Cornelius, who becomes a friend. Marius explores Rome in awe, and, "as a youth of great attainments in Greek letters and philosophy", is appointed amanuensis to the Emperor Marcus Aurelius. Aurelius's Meditations on Stoicism and on Plato, and the public lectures of the rhetorician Fronto, open Marius' eyes to the narrowness of Epicureanism. Aurelius's indifference, however, to the cruelty to animals in the amphitheatre, and later to the torments inflicted on people there, causes Marius to question the values of Stoicism (end of 'Part the Second'). Disillusioned with Rome and the imperial court which seem "like some stifling forest of bronze-work, transformed as if by malign enchantment out of the living trees", puzzled by the source of Cornelius's serenity, still Epicurean by temperament but seeking a more satisfying life-philosophy, Marius makes repeated visits alone to the Campagna and Alban Hills, on one occasion experiencing in the Sabine Hills a sort of spiritual "epiphany" on a perfect day of peace and beauty (end of 'Part the Third'). Later he is taken by Cornelius to a household in the Campagna centred on a charismatic young widow, Cecilia, where prevails an atmosphere of peace and love, gradually revealing itself as a new religion with liturgy and rituals that appeal aesthetically and emotionally to Marius. The sense of purposeful community there, set against the persecution of Christians by the authorities and the competing philosophical systems in Rome, contributes to Marius' mood of isolation and emotional failure. Overshadowed by thoughts of mortality he revisits home and pays his respects to the family dead, burying their funerary urns, and sets out again for Rome in Cornelius's company. On the way the two are arrested as part of a sweep of suspected Christians. It emerges that only one of the young men is of this sect, and Marius, unbeknown to Cornelius, makes their captors believe it is he. Cornelius is set free, deceived into thinking that Marius will follow shortly. The latter endures hardship and exhaustion as he journeys captive towards Rome, falls ill, and dying is abandoned by his captors. "Had there been one to listen just then," Pater comments, "there would have come, from the very depth of his desolation, an eloquent utterance at last, on the irony of men's fates, on the singular accidents of life and death."  Marius is tended in his last days by some poor country people, secret believers who take him to be one of their own. Though he has shown little interest in the doctrines of the new faith and dies more or less in ignorance of them, he is nevertheless, Pater implies, "a soul naturally Christian" (anima naturaliter christiana ) and he finds peace in his final hours as he reviews his life: "He would try to fix his mind on all the persons he had loved in life, dead or living, grateful for his love or not. In the bare sense of having loved he seemed to find that on which his soul might 'assuredly rest and depend'. ... And again, as of old, the sense of gratitude seemed to bring with it the sense also of a living person at his side" (end of 'Part the Fourth').
Output: Why are Marius and Cornelius arrested as they are returning to Rome?