Hey there, I just got your message and clicked on your journal. I think this might be a question I can answer: when they first invented the solfege system, with my man Guido d'Arezzo and his hand, you could put the ut in one of several positions. The thing was, the lowest note they could notate was called Gamma (and the highest was an "ut", hence the word gamut meaning the full range, which is a contraction of Gamma-ut), but you will notice that the syllables they originally had, ut re mi fa so la, don't cover the whole octave and only contain one semitone (between mi and fa). Thus, a major part of learning the method was about fitting the right syllables to the right parts of the chant. "Ut" was never a specific pitch, not even a specific notated pitch (because what they called "A" for example, varied by as much as a major third within Italy alone), and even within one piece, ut could appear as several different pitches. (Once modality was replaced by tonality, the system changed, and someone invented "ti" and also a whole variety of ways to inflect a tonal solfa system to account for accidentals.)

If you want to learn how to sing Guido's solfa, there are various sources that are helpful, not least the picture of the guidonian hand.

I don't know whether that was all stuff you already knew, or, on the contrary, completely incomprehensible . . . ?

ps. I'm delighted to have been friended! :)