Synesius of Cyrene (c.370-c.413) was a Neo-Platonic philosopher who became bishop of Ptolemais in the Cyrenaica. He left behind a small corpus of texts that offer much information about daily life in Late Antiquity, and about the christianization of the Roman world.
Synesius' On dreams consists of two parts:
- A philosophical explanation why dreams allow our soul to reach higher spheres, based on a doctrine that is derived from the philosophical school known as Stoa (sections1-7);
- A more down-to-earth, and very accessible, account of the way one must investigate one's dreams, which boils down to keeping a "night book"(section 8-13).
The text is offered here in the translation by A. Fitzgerald. The four-digit numbers are page numbers of the Migne edition.
Synesius, On dreams 6
 Let what has been said suffice concerning the destiny which the elements play. It is open to you to believe it or to disbelieve. But as to the corporeal essence which has come from thence, there is nothing to prevent it, when the soul ascends according to the law of nature, from rising out of its fallen state, from ascending with it and becoming linked with the spheres, that is to say, being carried up as if to its own natural state of being.
 There are, then, these two extreme lots, the one encircled by the darkness and the other encircled by the light, which occupy the limits of good and evil fortune. But in the hollow gulf of the universe how many intermediate places do you think there are, partly obscure and partly luminous, in all of which the soul has its habitation, together with this spirit envelope,note changing with its ideas and morals and life? When it hastens aloft to its native nobility, it is a store-house of truth, for it is pure, brightly shining, and unmixed, being a goddess and, if it so desires, a prophetess;  but when it falls, it becomes befogged, it lacks definiteness, it speaks falsely, for then the misty element of the spirit envelopenote does not comprise the vitality of existing things.
 And being in a medial position it would miss some truth although it might reach others. You might thus discern to what rank the demoniac nature belongs. To state the truth either entirely or almost entirely, it is divine, or near to the divine. Error in predictions of the future is a never-ending experience; passion and ambition belong to those who wallow in matter. It is in this way that the new-boiled wine puts on the guise both of a god and a superior demon and leaps in and takes possession of the country reserved for the greater nature.
 Now since man has a soul, we might from that source discover what his position may be. Of a man's imaginative pneuma is pure and well-defined, and whether he is waking or sleeping receives true impressions of things, it promises him a better lot, so far as the soul's formation is concerned. Then again it is not least by the visions which it emits and around which it lives, when undisturbed by another outside force, that we investigate what is the state of the spiritual pneuma, and philosophy, the while, furnishes us with tests to this end, so that we must of necessity cherish it and together see it to that we do not at any time wander.
 Now the best nurture for us is that we should become active by the force of application, anticipating the onsets of weird and headlong visions, and that the emanation of life should be, as far as possible, once for all intellectual: for this is to be turned towards the best and delivered from the worst, and to hold intercourse with (material) things only as necessity entails. Intellectual application is the most incisive weapon against those things which combine to injure the pneuma, for this mysteriously refines it and raises it towards God; and when it has become adapted to it, draws the divine spirit envelopenote by its kindred nature to association with the soul. In like manner, whenever it becomes compressed by reason of its density and grows too small to fill the places assigned to it by the providence which has molded man, to wit, the cavities of the brain; then since nature abhors a vacuum in existing things, an evil spirit envelopenote enters in; and what suffering for the soul with such an ill-omened guest at its board!
 For as to those places which have come to exist for this very purpose of belonging to the pneuma, it is their nature to be occupied by a worse or by a better one. In the one case there is a penalty for the godless who have defiled the divine part in them, in the other there is the goal of piety or whatsoever is near to that goal.