Ladders- the Seven +1 Gates.

THE FIFTH TABLET

From the Enuma Elish.

He (Marduk) made the stations for the great gods;

The stars, their images, as the stars of the Zodiac, he fixed.

He ordained the year and into sections he divided it;

For the twelve months he fixed three stars.

After he had ... the days of the year ... images,

He founded the station of Nibir to determine their bounds;

That none might err or go astray,

He set the station of Bel and Ea along with him.

He opened great gates on both sides,

He made strong the bolt on the left and on the right.

In the midst thereof he fixed the zenith;

The Moon-god he caused to shine forth, the night he entrusted to him.

Sigillum Dei Aemeth- Seal of the truth of God: The sigil predates Dee, having first appeared in a thirteenth century grimoire; it was later described by Athanasius Kircher in his Oedipus aegyptiacus. Used by Dee as a protective device.

From a gold plate found in Thurii, Southern Italy, 4th century BCE.

Pure I come from the pure, Queen of those below the earth,

and Eukles and Eubouleus and the other immortal gods;

For I boast that I am of your blessed race.

But Fate mastered me and the Thunderer, striking with his lightning.

I flew out of the circle of wearying heavy grief;

I came on with swift feet to the desired crown; 

I passed beneath the bosom of the Mistress, Queen of the Underworld, 

I came out with swift feet from the desired crown.

"Blessed and enviable one, a god you shall be instead of a mortal."

A kid I fell into milk.

The idea of a zombie like existence after death, as described by Homeric texts, has never been popular. It is not nice to think of the Sumerian underworld- a domain of ash- the fate for those who do not have their name remembered, or relatives left to tend the grave .

The alternative, the hope of a better life after death in a heavenly paradise, or in the company of the  gods, or 'enlightenment' is an optimism that seems to have taken root in Greek writing, slowly from the sixth century BC onwards.

In 669BC, Assyrians from Mesopotamia conquer Egypt. The Assyrian rule didn't last long; in 525BC, the Persians conquered Egypt and ruled the country until about 404BC, when a revolt earned the country its freedom for about 60 years before Persia attacked again..

The short answer to the question- why was there a change in Greek ideas about the Underworld- is that Egyptian and 'Persian'  beliefs and mythology diffused into Greek thought because of what was happening in Egypt. Of course it is more complex than that, but broadly speaking....The ladder to the stars- the abode of the divine- is an image that has its origin in the Assyrian Tree of Life, and remains today as the Cabala.

The other way to see 'the tree' is to see, instead a fountain:

The clearest evidence for a 'Persian ' influence extending beyond 'Persia' is the Avesta: Khorda Avesta: 10. MIHR YASHT ("Hymn to Mithra"). [LINK]

The Mithraic path to the stars, the seven plus one gates, is explained by Celsus, via Origen (hardly a fan of Celsus), and recorded by A S Geden:

Celsus following Plato affirms that souls proceed to and from the earth by way of the planets...and further being desirous of exhibiting his learning in controversy with us he expounds certain Persian mysteries also, and among them the following: "These doctrines are contained in the traditions of the Persians and in the cult of Mithra which they practise. For the latter gives a kind of representation of the two heavenly spheres, the one fixed and the other assigned to 'the planets, and of the journey of the soul through these. There is an ascending road with seven gates, and an eighth at the summit. The first gate is of lead, the second of tin, the third of bronze, the fourth of iron, the fifth of mixed metal, the sixth of silver, and the seventh of gold. The first is dedicated to Kronus, the lead symbolizing the planet's slow motion. The second to Aphrodite, the resemblance consisting in the bright and malleable nature of the tin. The third, firm and resistant, to Zeus. The fourth to Hermes, in that like the iron Hermes is the tireless and efficient worker and producer of wealth. The fifth to Ares, because of the variable and irregular nature of the alloy. The sixth, of silver, to the Moon; and the seventh, of gold, to the Sun, from a comparison of their colours." Later Celsus investigates the reason for this definite assignment of the stars in whose names the remainder of the physical universe finds symbolical expression, and he expounds further the doctrines of harmony in which the Persian theology is set forth. In addition to these he is so ambitious as to publish a second treatise dealing with the principles of music. In my judgement however, for Celsus to propound his theory in these is absurd; it is like his procedure in the matter of his denunciation of Christians and Jews where he makes irrelevant quotations from Plato, and is so far from being satisfied with these that he drags in the Persian mysteries as he calls them of Mithra also with all their details. For whether these things are true or false in the belief of those who preside over the Mithraic rites of the Persians, why did he choose them for exposition and interpretation rather than any other mysteries? for Greeks have no preference for mysteries of Mithra rather than those of Eleusis or the traditional rites of Hecate which they celebrate in Aegina. And why if he felt it incumbent upon him to set forth foreign mysteries did he not rather prefer the Egyptian, in which many take an interest, or the Cappadocian worship of Artemis in Comana, or the Thracian, or even those of the Romans themselves in which the most high-born senators take part? but if he regarded it as unsuitable to his purpose to adopt anyone of these on the ground that they furnished no support to his denunciation of Jews or Christians, how is it that he did not draw the same conclusion with regard to his exposition of the Mithraic rites? (Geden)

It is tempting to see the Egyptian 'Book of Gates' (specifically the 12 Gates portrayed in the tomb of Thutmose III -1479-1425 BC) as something similar: the 'Boat of Millions' sails the sea of stars, crossing through deserts and across fearful abysses and over round barrow to beat all round barrows- the Hill of Sokar...[LINK].

No ladders in the boat, though!