Ut que-ant la-xis
Re-so-na-re fi-bris
Mi-ra ge-sto-rum
Fa-mu-li tu-o-rum
Sol-ve po-lu-ti
La-bi-i re-a-tum
Sanc-te Io-han-nes
Musical notation of Gregorian chant.
So that your servants may
with loosened voices
resound the wonders of your deeds
of your deeds
clean the guilt
from our stained lips
O Saint John
Translation: “Wikipedia”
Guido d’Arezzo, he lived approximately from 990 up to 1050, has at a moment in his life put the notes of "Ut queant Laxis" on a row and named them. These names are the beginning characters of the rules of the hymne: Ut – Re – Mi – Fa – Sol – La and Si.
Because of consonance-false-driven of Ut in English Do is used.
This denomination of music is relative and one can start on another, random, altitude, for example a note higher or a note lower.