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).