Actually, looking further at this (and trying to get at least some science into this thread), tuning A to 432Hz lowers it by a bit less than a quarter tone, as you can interpolate from the attached:
http://www.phy.mtu.edu/~suits/notefreqs.html
(I also checked this on my electronic tuning fork.)
Lowering it a semitone takes A to 415Hz. This, or something like it, is what is often called "Baroque pitch" , which is often used nowadays for authentic-sounding performances of pre-1850 music. There was in fact little standardisation in earlier times, as illustrated in this piece of research on old tuning forks:
http://www.mozartpiano.com/articles/pitch.php
I note the various crystals-and-shit sites repeat the statement that "ancient" instruments were all tuned to to A=432Hz. This assertion seems to be quite baseless. It is also intuitively unlikely, as the difficulties of travel would have made widespread agreement on pitch even less relevant than in the c.17th and 18th.
So, almost certainly, a load of old cobblers, unsurprisingly.
(As a baritone singer, I am always relieved when Baroque choral music is played at Baroque pitch. Handel in particular, writes exquisitely for the voice and his bass parts almost never go below G, whereas the top end can be quite high at modern concert pitch. At Baroque pitch it is all comfortable. Bach is a different kettle of fish, making no concessions whatever to the limitations of the voice, so it matters little what pitch is chosen, it is aways tough.)