The origin of "do - re - me - fa - so - la - ti - do"
Paulus Diaconis (Paul the Deacon) , who died in 799, was a historian and poet. He wrote a poem (in Latin, as was the norm back then) about John the Baptist.
Guido d'Arrezzo was a musician who lived about 200 years later. He developed the modern musical staff notation. (Although he might not have been the first to use something like that.) But he is probably most famous for what he did with a hymn that had set Paulus' poem to music.
(There is no consensus as to whether Guido actually wrote the music.)
The piece starts on middle C. Note that the musical phases progress up the scale for a while, each one beginning with what we call C D E F G A in turn, before dropping in pitch on the last phrase.
Guido decided to name each of the six notes according to the Latin syllable on which they fell:
ut - re - mi - fa - sol - la
Over time, "ut" became "do" , some people sang "so" for "sol", and the seventh note got added as "si."
This addition happened much later. Classical Latin used "i" for both our letters "i" and "j", and medieval Latin was a bit inconsistent with the two letters after "j" was introduced. I am guessing that SI comes from the initials Sancte Ioannes (Saint John) in the final phrase,
Nowadays the seventh note is often given as "ti". (There is a song in the musical "The Music Man" during which the chorus sings the scale, and the lyrics contain "si". But of course Julie Andrews made "a drink with jam and bread" famous in "The Sound of Music.")
I learned that Do Re Mi song in Kindergrten, which I later heard from the 1965 film, The Sound of Music.
Do. A deer. A female deer. Re. A drop of golden sun. Mi. A name, I call myself. Fa. A long-a-way to run. So. A needle pulling thread. La. A note to follow So. Ti. A drink with jam and bread.
@DrWatson That "Do Re Mi" song is what's also known as a mnemonic, which is a way to commit information to memory.
Other examples of mnemonics include "Roy G. Biv" as a way of remembering the sequence of colors in the rainbow. (Red, Orange,Yellow, Green, Blue, Indigo, and Violet)
As well The rhyme: "30 days has September, April, June and November"
@Sidewinder I think, historically, do-re-mi, etc, were the actual names of the notes, not a short-cut. Our notation A, B, C, D, E, F, G came later. And in fact, at times other letters were used. For example, for a while H was used to denote a note (I forget which -- one of the sharps or flats), which allowed Johann Sebastian BACH to famously "sign his name" with the final four notes of one of his pieces!
People can learn to sing without ever learning to read music. And at first, there was no way at all to read music because people had not yet figured out a way to write it down or had come up with a way to refer to tones by name. That was Guido's contribution.
So this seems to me to be reversed from the usual idea of a mnemonic. The list ut, re, mi, fa, so, la, is analogous to Red, Orange, Yellow, Green, Blue, Indigo, Violet. And the memory device is the hymn, which gives meaning to those nonsense syllables. So the hymn itself is analogous to Roy G Biv. The mnemonic is longer than the actual thing!
@LeopoldBloom My first inkling about this came from working crossword puzzles, where I would find the clue "Guido's high note."
I had no idea what that meant.
Then one day, I was looking up the word "gamut" in a (print) dictionary because I was curious about the etymology. The entry referred to Guido and went into solfege at length, giving the entire verse of the Latin hymn.
Since then, I have become interested in Latin and came across Paul the Deacon, and that all led back to Guido!
But I am still not sure of why the answer to that crossword clue is ELA.