Hi Hearsay:

I was previewing the 1939 film "Goodbye Mr Chips" this afternoon prior to screening it tomorrow night. There's a scene in it when Mr Chips (now an old man) complains about being told to teach the 'new-fashioned'(ie turn-of-the-century) Latin style of using a hard 'C'. He says why should I teach them to pronounce it [Kikero] when they'll say [Cicero - soft 'C'] for the rest of their lives?

So, was there a pronunciation change around that time?