This description of JS Bach is taken from Johann Matthias Gesner’s edition of Marcus Fabius Quintilianus’ Institutio oratorio (1738). Gesner added the description as an illustration of Quintilianus’ point that a person can do many things at the same time. The original is in Latin.
This, Fabius, you would deem to be wholly unimportant if, recalled from the underworld, you were able to see Bach – to mention only him, for not so long ago he was my colleague at St. Thomas’s School in Leipzig-playing with both hands and all fingers out clavier, for example, an instrument that comprises many kitharas. Or that fundamental instrument, the innumerable pipes of which are supplied with air by bellows, how here he hurries with both hands over the keys, and there with swift feet, and alone produces as it were hosts of quite different and yet fitting notes. If you saw him, I say, how, in a manner never attained by many of your kithara players and innumerable flautists, he not only sings one melody like the kithara player maintains his own part, but also pays attention to al simultaneously, and encourages from thirty to forty musicians to observe the rhythm and the beat, this one with a nod, the next by stamping his feet on the ground, the third with a threatening finger, the one his note in the top range, the other in the low range, and the third in the middle. How all alone in the midst of the loudest passages played by the musicians, though having the most difficult part himself, he notices none the less if something is amiss; how he holds them all together, giving a helping hand everywhere; and if they are assailed by doubt, he immediately restores order; how he feels the beat in arms and legs, scrutinising the harmonies with a sharp ear, alone bringing forth all the voices with his own limited throat. In all other things a passionate admirer of antiquity, I believe that friend Bach alone, and those who resemble him, surpass Orpheus several times, and Arion at least twenty times.
Quoted in: Badura-Skoda, Paul, trans. Alfred Clayton, Interpreting Bach at the Keyboard, Clarendon Press, Oxford, 1993, ISBN 0-19-816155-7, Appendix 3. The source for the quotation is Bach-Dokumente, ii. Fremdschriftliche und gedruckte Dokumente zur Lebensgeschichte Johann Sebastian Bachs 1750-1800, ed. H.-J. Schulze, Kassel and Leipzig, 1969, p. 332 f.
Theory of Music 