There is a tradition in classical epic of two Gates of Sleep, one of horn and one of ivory. Through the ivory one comes deceptive dreams, and through the horn gate comes true dreams that will be fulfilled. These gates are first mentioned in the Odyssey, where Penelope states that she dreamt an eagle flew down and killed 20 geese (the implication being that Odysseus is the eagle and the geese are the suitors who are desecrating his home). However she then questions whether or not her dream will come true:
“My friend, dreams are things hard to interpret, hopeless to puzzle
out, and people find that not all of them end in anything.
There are two gates through which the insubstantial dreams issue.
One pair of gates is made of horn, and one of ivory.
Those of the dreams which issue through the gates of sawn ivory,
these are deceptive dreams, their message is never accomplished.
But those that come into the open through the gates of the polished
horn accomplish the truth for any mortal who sees them.”
In the scholia for this passage (that is, the ancient commentaries) it is explained that horn is a reference to the eyes, because the ‘outer membrane of the eye is hornlike in appearance’, whereas ivory refers to the mouth, because teeth are ivory coloured. Therefore the implication is that things seen are more reliable than things spoken.
However, by far the most interesting reference to the Gates of Sleep comes in Virgil’s epic about the founding of Rome: the Aeneid. In Book Six Aeneas journeys down to the underworld with a prophetess called the Sibyl, where the soul of his father Anchises tells him his destiny as the founder of the Roman Empire. In many ways this book is extremely celebratory, praising the glory of Rome. This is how it has long been understood, with generations of schoolboys being taught to read Virgil as the great champion of the Roman nation, no doubt inspiring the great Western empire- and nation-builders of the 19th century.
It is has since been shown that there is much more to Virgil’s epic. Scholars have detected in the Aeneid a profound sensitivity to the human suffering that is the result of Aeneas’ mission. Book 6 is particularly responsive to such readings. In the underworld Aeneas is shown a pageant of the future heroes of Rome and told about their great deeds, firing him up with a patriotic ‘love for the glory that was to come‘ (6.889). But the book then has an unexpected ending. In order to leave the underworld, Aeneas must pass through the Gates of Sleep:
“There are two gates of sleep: one is called the Gate of Horn and it is an easy exit for true shades; the other is made all in gleaming white ivory, but through it the powers of the underworld send false dreams up to the heavens. Here on the night did Anchises walk with his son and with the Sibyl and spoke such words to them as he sent them on their journey through the Gate of Ivory.”
Aeneas leaves through the Gate of Ivory, the gate of false dreams.