This system we know today as Solmisation. He put notes to music staff which had 4 lines (instead of 5,what we have today) and gave the sylable for each pitch. Who knows? Italian theorist, Guido d'Arezzo, organized notation of already existed music. So, maybe this letter 'B' fitted better for B flat pitch.
From 'D'- DEFGAB (B sounds like real B natural) From 'E'- EFGABC From 'F'- 'B' doesn't sound well (Lydian mode doesn't exist yet). Pretend we form hexachord from note 'C': we have CDEFGA. So, probably when this hexachord was formed from 'F' note, there was no letter for B flat. I heard this version: the letter 'b' looks like flat, and the letter 'h' looks like natural.īTW, I am back to hexachords. Later, for B note was used the letter 'H' (next to 'G'). The lowest pitch was named 'A' following by B (which was sounded like B flat), C, D, E, F, G. Hexachord is diatonic 6th stepped mode which related to Greek music of 9th century. Maybe the reason goes to history of hexachords. Inge, that's very interesting question.