When did J.R.R. Tolkien write the verse found on the One Ring?

Question

J.R.R. Tolkien spent many years creating his "Legendarium" - often writing stories decades before using them as foundational elements of his later work. He would also regularly revise individual works as the story evolved during his creative process. Tolkien himself mentions that he would write a specific section of the story that was of crucial import from which he would expand through multiple drafts, sometimes with long periods of time between efforts :

As the story grew it put down roots (into the past) and threw out unexpected branches: but its main theme was settled from the outset by the inevitable choice of the Ring as the link between it and The Hobbit. The crucial chapter, "The Shadow of the Past', is one of the oldest parts of the tale. It was written long before the foreshadow of 1939 had yet become a threat of inevitable disaster, and from that point the story would have developed along essentially the same lines, if that disaster had been averted. ^{Lord of the Rings : Fellowship of the Ring : Prologue}

Knowing the propensity that Tolkien had for establishing mythological and folkloric narratives as building blocks for his world building I have begun to wonder in what order he wrote important elements and themes.

The One Ring has the following poem, which itself is part of a longer verse, written on it in letters of fire :

One ring to rule them all, one ring to find them, One ring to bring them all and in the darkness bind them.

I won't utter them in the tongue or Mordor here.

when was the poem found on the One Ring written relative to the rest of Tolkien's "legendarium"?

The answer would ideally contain a real time date and position relative to his major works (example: during the writing of The Lay of Beren and Luthien).

Answer 1

Early in the writing of Fellowship; mid-to-late 1938

The Ring-verse, and the larger poem, appear in what I'm going to tentatively call the fifth draft of the chapter that would become "Shadows of the Past"; it came some time after Tolkien abandoned his first attempt at the story, settling for what he, in a note, called a "simplified version":

'Hold it up!' said Gandalf, 'and look inside.' As Bingo did so he saw fine lines, more fine than the finest pen strokes, running along the inside of the Ring - lines of fire that seemed to form the letters of a strange alphabet. They shone bright, piercingly bright, and yet it seemed remotely, as if out of a great depth.

'I cannot read the fiery letters,' said Bingo in a quavering voice.

'No,' said Gandalf; 'but I can - now. The writing says:

One Ring to rule them all, One Ring to find them,
One Ring to bring them all, and in the darkness bind them.

That is part of a verse that I know now in full.

^{History of Middle-earth VI The Return of the Shadow Part 2: "The Second Phase" Chapter XV: "Ancient History"}

I'm quite confident that it didn't appear before this, not least because this is the first appearance of it in History of Middle-earth, but also because the idea of the One Ring as the Ruling Ring itself didn't enter the story until the second phase of Fellowship; Christopher Tolkien remarks on the entrance of that idea in a list of notes titled "Queries and Alterations", written by Tolkien after the abandonment of the "first phase":

At this time also he underlined the words 'Why did the Dark Lord desire it so?', put an exclamation mark against them, and wrote:

Because if he had it he could see where all the others were, and would be master of their masters - control all the dwarf-hoards, and the dragons, and know the secrets of the Elf-kings, and the secret [? plans] of evil men.

Here the central idea of the Ruling Ring is clearly present at last, and it may be that it was here that it first emerged.

^{History of Middle-earth VI The Return of the Shadow Part 1: "The First Phase" Chapter XIII: "Queries and Alterations"}

It's hard to nail down a precise date, but Christopher Tolkien attempts to date his father's "third phase" (this excerpt belongs to the second) later in the book, and suggests that it was begun after October 1938:

My guess - it can hardly be more - is that in October 1938 the third phase had not been begun, or had not proceeded far, since the boot was 'in rather an illegible state', while when my father wrote of having had to set the work aside in December 1938 it was to the third phase that he was referring

^{History of Middle-earth VI The Return of the Shadow Part 3: "The Third Phase" Chapter XIX: "The Third Phase (1): The Journey to Bree"}

And earlier he described some late notes on the "first phase" as being likely dated to late summer of 1938; so we can presumably place this text somewhere in that range, likely closer towards the summer than the autumn.

At this time, Tolkien wasn't doing substantial work on the rest of the legendarium, as Christopher Tolkien notes in the preface to The Lost Road:

This fifth volume of The History of Middle-earth completes the presentation and analysis of my father's writings on the subject of the First Age up to the time at the end of 1937 and the beginning of 1938 when he set them for long aside.

^{History of Middle-earth V The Lost Road and Other Writings Preface}

Answer 2

Between December 1937 and September 1939

Tolkien's son Christopher has written extensively about the writing of The Lord of the Rings in volumes 6-8 of The History of Middle-Earth. While he presents many different drafts of the text, he doesn't always give them a date (he may not always have been able to date them.

However, I think we can place the writing of the Ring-verse somewhere between December 1937 (when Tolkien began writing a sequel to The Hobbit) and September 1939 (when World War II began - the quote in the question makes clear the *The Shadow of the past was written before the outbreak of the war).

The original written starting-point of The Lord of the Rings - its 'first germ', as my father scribbled on the text long after - has been preserved: a manuscript of five pages entitled A long-expected party. I think that it must have been to this (rather than to a second, unfinished, draft that soon followed it) that my father referred when on 19 December 1937 he wrote to Charles Furth at Allen and Unwin: 'I have written the first chapter of a new story about Hobbits - "A long expected party".'

_{The History of Middle-Earth Volume VI, Chapter 1: A long-expected party}

It is unlikely that the Ring-verse had been composed earlier than this as Tolkien had not yet settled on the idea of Bilbo's Ring being the Ruling Ring.

In this first phase of writing, Bilbo's ring was not the Ruling Ring, but simply the last ring that "the Lord" had not yet retrieved

... till at last he had gathered all into his hands again that had not been destroyed by fire - all save one.

'It fell from the hand of an elf as he swam across a river; and it betrayed him, for he was flying from pursuit ...

_{The History of Middle-Earth Volume VI, Chapter 3: Of Gollum and the Ring}

The first draft of what would become the second chapter of The Lord of the Rings was written during the second phase of writing.

A Chapter titled 'II: Ancient History', precursor of 'The Shadow of the Past' in FR, was now introduced to follow 'A Long-expected Party'. It is of central importance in the evolution of The Lord of the Rings: for it was here that there emerged in the actual narrative the concept of the Ruling Ring.

_{The History of Middle-Earth Volume VI, Chapter 15: Ancient History}

The chapter quoted above also includes the early draft that contains the text of the Ring-verse and an image of the manuscript that contains it.