Damoetas wrote:Without spending some time in the library, I'm not sure how to confirm whether or not Marcus Aurelius also said it.
Marcus Aurelius Antoninus (Thoughts, trans. Long, 1889) wrote:III.7 for he who has preferred to everything else his own intelligence and daemon and the worship of its excellence, acts no tragic part, does not groan, will not need either solitude or much company; and, what is chief of all, he will live without either pursuing or flying from death...
XII.3 ...and if thou shalt strive to live only what is really thy life, that is, the present, — then thou wilt be
able to pass that portion of life which remains for thee up to the time of thy death free from perturbations, nobly, and obedient to thy own daemon [to the god that is within thee]