Read this and answer the question. If the question is unanswerable, say "unanswerable".

Constantine's nephew Julian rejected the "Galilean madness" of his upbringing for an idiosyncratic synthesis of neo-Platonism, Stoic asceticism and universal solar cult. Julian became Augustus in 361 and actively but vainly fostered a religious and cultural pluralism, attempting a restitution of non-Christian practices and rights. He proposed the rebuilding of Jerusalem's temple as an Imperial project and argued against the "irrational impieties" of Christian doctrine. His attempt to restore an Augustan form of principate, with himself as primus inter pares ended with his death in 363 in Persia, after which his reforms were reversed or abandoned. The empire once again fell under Christian control, this time permanently.

When did Julian become Augustus?
361