Ornamentation in JS Bach's C-sharp minor prelude, Well-Tempered Clavier, Book 1

[andrewlindsley]

Please can you advise me on the appoggiatura followed by trillo in the second bar of Bach's C-sharp minor prelude, WTC, Book 1 — and so by implication all related phrases? In other words, in 6/4 time, how long should the appoggiatura last — a quaver (eighth note)? a crotchet (quarter note)? a dotted minim (dotted half note)? Would the trillo then start on the upper auxilliary A, thus repeating the A of the appoggiatura, or start on the main note G-sharp? I have tried to find out from books and articles on Baroque ornamentation but am not clear how Bach would have expected his conmtemporaries to combine the two ornaments in this context.

[lelle]

I played the appogiaturas freely around the duration of an eighth note, starting the trill on the lower note, but tying it together with the appgoggiatura, so to speak.

[andrewlindsley]

Thank you for replying. Very helpful.