The mouth of the river begins at a 2006 film, now available on Netflix: "The Painted Veil". Earlier versions of Somerset Maugham's 20th century novel exist, I've seen at least one other adaptation. It's a gloomy tale with mainly irritating characters, but it has survived at least three film adaptations.
Following the first bend in this "river": the book and film's title came from a sonnet by Percy Bysshe Shelley (1792-1822).
Lift not the painted veil which those who live
Call Life: though unreal shapes be pictured there,
And it but mimic all we would believe
With colours idly spread,--behind, lurk Fear
And Hope, twin Destinies; who ever weave
Their shadows, o'er the chasm, sightless and drear.
I knew one who had lifted it--he sought,
For his lost heart was tender, things to love,
But found them not, alas! nor was there aught
The world contains, the which he could approve.
Through the unheeding many he did move,
A splendour among shadows, a bright blot
Upon this gloomy scene, a Spirit that strove
For truth, and like the Preacher found it not.
The sonnet can be read in various ways, a comment at a website presenting the sonnet offered this:
Life is an illusion, and most are clueless people who play along with the backdrop provided. Shelley is playing the role of a wise man giving us the famous warning: innocence and even ignorance may be the best path to stick with, since to be wise is to suffer.
The famous “painted veil” which reveals life in line 1 can be a metaphor for many things: love (as described in line 8), death, or even truth (as described in the final line).
The sonnet was published by Mrs. Shelley in Posthumous Poems, 1824.
Searching further - this "river's" source still lies ahead. Some of the lines from Shelley's sonnet also appeared in his 1820 play "Prometheus Unbound". These words are part of a speech by Spirit of the Hour, Act 3, Scene4.
The painted veil, by those who were, called life,
Which mimicked, as with colors idly spread,
All men believed and hoped, is torn aside;
The loathsome mask has fallen, the man remains
Sceptreless, free, uncircumscribed, but man
Equal, unclassed, tribeless, and nationless,
Exempt from awe, worship, degree, the king
Over himself; just, gentle, wise; but man
Passionless--no, yet free from guilt or pain,
Which were, for his will made or suffered them;
Nor yet exempt, though ruling them like slaves,
From chance, and death, and mutability,
The clogs of that which else might oversoar
The loftiest star of unascended heaven,
Pinnacled dim in the intense inane.
Prometheus Unbound is a four-act lyrical drama by Percy Bysshe Shelley, first published in 1820. It is concerned with the torments of the Greek mythological figure Prometheus, who defies the gods and gives fire to humanity, for which he is subjected to eternal punishment and suffering at the hands of Zeus. It is inspired by the classical Prometheia, a trilogy of plays attributed to Aeschylus. Shelley's play concerns Prometheus' release from captivity, but unlike Aeschylus' version, there is no reconciliation between Prometheus and Jupiter (Zeus). Instead, Jupiter is abandoned by his supportive elements and falls from power, which allows Prometheus to be released.
Aeschylus, (born 525/524 BC — died 456/455 BC, Gela, Sicily) the first of classical Athens’ great dramatists, who raised the emerging art of tragedy to great heights of poetry and theatrical power.
This river flows all the way from ancient Greece to the 21st century, via Aeschylus, Shelley, Maugham, and several 20th and 21st century film-makers. Yep, cool!
