Was alto in the past lower in pitch than where they are today?

Question

I wonder why alto clefs are so low that they doesn't seem to match the range of alto(female low voice). Why did J.S. Bach use alto clef so much for the middle part of his fugue? Is it because alto was lower in the past?I just cannot understand why the clef Bach used for alto was almost one octave lower that the clef used in modern alto, which is treble clef.

Answer 1

Most altos can sing all the way to F3, or some even lower. In typical choral music, they wouldn't sing above a C5 or D5 either. In treble clef, this would cause the need for many ledger lines at the bottom, and the part would overall fit better in the alto clef. I sing alto myself, and although I was not trained to read alto clef from the beginning, it visually makes more sense in the voice than reading a bunch of ledger lines. The more straightforward answer is that movable clefs were also just a part of common practice choral composition at the time. Bach may have found tenors singing on a modern octave transposed treble clef quite strange.