Well there is a really fast silver bromide emulsion described in the french translation of JM Eder's book printed in 1883.
Home brewed in less than optimal conditions I obtained some 16 ISO plates, fare enough to make a 1/15th s exposure at f=12 in full sun. It worked at 1/60th and F2.

And some other emulsions from later sources (1885) quote ultra fast plates around 50 iso (according to an unaccurate adapation of the warneke's sensitometry system)

I'm not that amazed, but the images are just crazy!