Ovid, Metamorphoses: If you haven't read it, you should.

Until I get a chance to post a few dreams up here, this should keep you busy.
"[Hera commands her messenger Iris to summon a Dream-spirit :] `Iris, my voice's trustiest messenger, hie quickly to the drowsy hall of Somnus [Hypnos], and bid him send a dream of Ceyx drowned to break the tidings to [his wife] Alcyone.' Then Iris, in her thousand hues enrobed traced through the sky her arching bow and reached the cloud-hid palace of the drowsy king. Near the Cimmerii land a cavern lies deep in the hollow of a mountainside, the home and sanctuary of lazy Somnus, where the sun's beams can never reach at morn or noon or eve, but cloudy vapours rise in doubtful twilight; there no wakeful cock crows summons to the dawn, no guarding hound the silence breaks, nor goose, a keener guard; no creature wild or tame is heard, no sound of human clamour and no rustling branch. There silence dwells : only the lazy stream of Lethe 'neath the rock with whisper low o'er pebbly shallows trickling lulls to sleep. Before the cavern's mouth lush poppies grow and countless herbs, from whose bland essences a drowsy infusion dewy Nox (Night) distils and sprinkles sleep across the darkening world. No doors are there for fear a hinge should creak, no janitor before the entrance stands, but in the midst a high-raised couch is set of ebony, sable and downy-soft, and covered with a dusky counterpane, whereon the god, relaxed in languor, lies. Around him everywhere in various guise lie empty Somnia [Oneiroi, dreams], countless as ears of corn at harvest time or sands cast on the shore or leaves that fall upon the forest floor. There Iris entered, brushing the Somnia (Dreams) aside, and the bright sudden radiance of her robe lit up the hallowed place; slowly the god his heavy eyelids raised, and sinking back time after time, his languid drooping head nodding upon his chest, at last he shook himself out of himself, and leaning up he recognized her and asked why she came, and she replied : `Somnus, quietest of the gods, Somnus, peace of all the world, balm of the soul, who drives care away, who gives ease to weary limbs after the hard day's toil and strength renewed to meet the morrow's tasks, bid now thy Dreams, whose perfect mimicry matches the truth, in Ceyx's likeness formed appear in Trachis to Alcyone and feign the shipwreck and her dear love drowned. So Juno [Hera] orders.'
Then, her task performed, Iris departed, for she could no more endure the power of Somnus, as drowsiness stole seeping through her frame, and fled away back o'er the arching rainbow as she came. The father Somnus chose from among his sons, his thronging thousand sons, one who in skill excelled to imitate the human form; Morpheus his name, than whom none can present more cunningly the features, gait and speech of men, their wonted clothes and turn of phrase. He mirrors only men; another forms the beasts and birds and the long sliding snakes. The gods have named him Icelos; here below the tribe of mortals call him Phobetor. A third, excelling in an art diverse, is Phantasos; he wears the cheating shapes of earth, rocks, water, trees--inanimate things. To kings and chieftains these at night display their phantom features; other dreams will roam among the people, haunting common folk. All these dream-brothers the old god passed by and chose Morpheus alone to undertake Thaumantias' [Iris’] commands; then in sweet drowsiness on his high couch he sank his head to sleep. Soon through the dewy dark on noiseless wings flew Morpheus and with brief delay arrived at Trachis town and, laying his wings aside, took Ceyx‘s [ghostly] form and face and, deathly pale and naked, stood beside the poor wife‘s bed. His beard was wet and from his sodden hair the sea-drips flowed; then leaning over her, weeping, he said : `Poor, poor Alcyone! Do you know me, your Ceyx? Am I changed in death? Look! Now you see, you recognize--ah! Not your husband but your husband‘s ghost. Your prayers availed me nothing. I am dead. Feed not your heart with hope, hope false and vain. A wild sou‘wester in the Aegaeum sea, striking my ship, in its huge hurricane destroyed her. Over my lips, calling your name--calling in vain--the waters washed. These tidings no dubious courier brings, no vague report: myself, here, shipwrecked, my own fate reveal. Come, rise and weep! Put on your mourning! Weep! Nor unlamented suffer me to join the shadowy spirits of Tartara (the Underworld).’ So Morpheus spoke, spoke too in such a voice as she must think her husband‘s (and his tears she took for true), and used her Ceyx‘ gestures. Asleep, she moaned and wept and stretched her arms to hold him, but embraced the empty air. `Oh wait for me!’ she cried, `Why haste away? I will come too.’ Roused by her voice‘s sound and by her husband‘s ghost, now wide awake, she looked . . . but found him nowhere . . . She cried, `. . . He is dead, shipwrecked and drowned. I saw him, knew him, tried to hold him--as he vanished--in my arms. He was a ghost, but yet distinct and clear, truly my husband‘s ghost, though to be sure his face was changed, his shining grace was gone. Naked and deathly pale, with dripping hair, I saw him--woe is me!"
-Ovid, Metamorphoses 11. 585 (trans. Melville)