Years ago I read in one of Giuseppe Tucci's book on Tibetan Buddhism about the mythological history of the first Tibetan kings. It is said that the first Tibetan kings descended from heaven through rope-like structures called dmu-thag and after their time on Earth was up they returned back to heaven in a similar fashion.
Let me provide some references that I could quickly cobble together:
Tibetan mythology holds that the first kings were immortal, and would be pulled up to heaven by a cord which had first deposited them on earth. This is what is said to have happened to Nyatri Tsenpo as well.
Then there is the following article on the Tibetan mountain gods containing some rather interesting information:
The Mythology of Tibetan Mountain Gods: An Overview
by Xie Jisheng
The phrase for “heavenly rope” in Tibetan is dmu-thag-smu-thag. The word dmu appears relatively late in Tibetan literature. Dmu is written as mu in Dunhuang literature, and etymological comparisons between various Tibeto-Burmese languages strongly suggests that mu- in Tibetan refers to “the heavenly god.”15 As for the word dmu-thag, I believe it to be closely connected to the Tibetan word for “rainbow” (vjav). A rainbow could well be understood by early societies as a rope connecting heaven to earth, a rope sent down by the heavenly gods. Literally, dmu-thag means “the heavenly gods’ rope.” According to Tibetan literature, when the Tibetan king btsanpo died he looked like a rope under the “rainbow,” and he went up to the heavens along the dmu-thag. It seems, then, that there is an intimate relationship between dmu-thag and vjav. In Pelliot’s Tibetan text no. 126.2 (“The Formation of Dmu-thag”), we read that “from the lights in the sky and fog over the sea came the white curdle of the Bon religion. It is stretched by the wind, woven into threads, and wound round a tree. It is known as Dmuthag or g.yang thag (“fortune rope”).”16 This text clearly identifies dmuthag with the rainbow.
As a result, many Tibetan history books hold that the first generation of Tibetan kings (btsan-po) descended from the heavens to the sacred mountains. For example, in Tibetan Historical Texts in a Duhuang Version we find that nyag-khri-btsan-po descended to the mountain of lha-ri-byang-mtheo (“the sacred mountain towering high in the north”).
Please consider the fascinating connections between the dmu-thag i.e. "the heavenly rope" and the rainbow.
Perhaps I am comparing apples to oranges, but could there be a relation between the "Rainbow Body" of the Dzogchen tradition and the "immortal" kings of early Tibet, who also ascended to heaven in a rainbow-like fashion after concluding their reign on Earth?
It is interesting to note here that according to Choegyal Namkhai Norbu Rinpoche's book "The Crystal and the Way of Light: Sutra, Tantra and Dzogchen", page 129 (Chapter 8 - THE FRUIT), paragraph "The Great Transfer", the Dzogchenpa who achieves the "Rainbow Body of Great Transference" ('ja lus 'pho ba chen po) actually does not undergo the process of death at all i.e. not like with lower manifestations, where the pracitioner dies, but his body dissolves and only nails and hair remain.
Then I would further like to mix up the stew and add a quote from the Agganna Sutta
There comes a time, Vasettha, when, sooner or later after a long period this world contracts. At a time of contraction, beings are mostly born in the Abhassara Brahma world. And there they dwell, mind-made, feeding on delight, self luminous, moving through the air, glorious—and they stay like that for a very long time. But sooner or later, after a very long period, this world begins to expand again. At a time of expansion, the beings from the Abhassara Brahma world, having passed away from there, are mostly reborn in this world. Here they dwell, mind-made, feeding on delight, self-luminous, moving through the air, glorious and they stay like that for a very long time.
At that period, Vasettha, there was just one mass of water, and all was darkness, blinding darkness. Neither moon nor sun appeared, no constellations or stars appeared, night and day were not yet distinguished, nor months and fortnights, nor years and seasons; there was no male and female, beings being reckoned just as beings. And sooner or later, after a very long period of time, savory earth spread itself over the waters where those beings were. It looked just like the skin that forms itself over hot milk as it cools. It was endowed with color, smell, and taste. It was the color of fine ghee or butter and it was very sweet, like pure wild honey.
Then some being of a greedy nature said: "I say, what can this be?" and tasted the savory earth on its finger. In so doing, it became taken with the flavor, and craving arose in it. Then other beings, taking their cue from that one, also tasted the stuff with their fingers. They too were taken with the flavor, and craving arose in them. So they set to with their hands, breaking off pieces of the stuff in order to eat it. And the result was that their self luminance disappeared. And as a result of the disappearance of their self luminance the moon and the sun appeared, night and day were distinguished, months and fortnights appeared, and the year and its seasons. To that extent the world re-evolved.
And those beings continued for a very long time feasting on this savory earth, feeding on it and being nourished by it. And as they did so, their bodies became coarser, and a difference in looks developed among them. Some beings became good looking, others ugly. And the good looking ones despised the others, saying: "We are better looking than they are." And because they became arrogant and conceited about their looks, the savory earth disappeared. At this they came together and lamented, crying, "Oh, that flavor! Oh, that flavor!" and so nowadays when people say, "Oh, that flavor!" when they get something nice, they are repeating an ancient saying without realizing it.
And then, when the savory earth disappeared, a fungus cropped up, in the manner of a mushroom. It was of good color, smell, and taste. It was the color of fine ghee or butter, and it was very sweet, like pure wild honey. And those beings set to and ate the fungus. And this lasted for a very long time. And as they continued to feed on the fungus, so their bodies become coarser still, and the difference in their looks increased still more. And the good looking ones despised the others…and because they became arrogant and conceited about their looks, the sweet fungus disappeared. Next, creepers appeared, shooting up like bamboo…and they too were very sweet, like pure wild honey.
And those beings set to and fed on those creepers. And as they did so, their bodies became even coarser, and the difference in their looks increased still more…and they became still more arrogant, and so the creepers disappeared too. At this they came together and lamented, crying: "Alas, our creepers gone! What have we lost!" and so now today when people, one being asked why they are upset, say: "Oh what have we lost!" they are repeating an ancient saying without realizing it.
Could there also be a connection between the "Rainbow Body" of Dzogchen and the above quoted excerpt from Agganna Sutta i.e. humans being originally entities of light descending from a heavenly world and then losing their divine nature due to greed and other defilements?
There exist interesting parallels between the Agganna Sutta and certain streams of the Jewish mystical tradition, where too it is stated that in the beginning man was an androgynus being of light containing both female and male elements in perfect harmony and that when Tikkun HaOlam comes ("Reparation of the Worlds") man's original nature will be established again.
Sidenote: In light of the above quote from Agganna Sutta, where it is stated that these original beings of light were neither male nor female in the beginning, the whole historical as well as modern antagonism between male and female seems redundant. Male and female seem to be 2 complementary parts of one being. Neither of them being higher or lower, but rather different i.e. each having what the other needs. This also seems to be perfectly exemplified in certain so-called sexual practices of Tibetan Vajrayana, where the male and female practitioner provide for each other, what they individually lack or have trouble to obtain.
Looking forward to your feedback and opinions.