First, a stipulated definition (with apologies in advance to PvI for not following his terminological guidelines): let free will be the control condition on moral responsibility.
Now, the historical question. What, if any, philosophers denied the existence of free will prior to, say, 1900? (This is an arbitrary time; I'm actually most interested in whether any ancient, medieval, or modern philosophers denied the existense of free will.)
Bonus question for those who answer the historical question: What reasons were given to support FW skepticism?