Conversation so far:
when did Frederick Douglass become an abolitionist?
In 1843.
what did he do as an abolitionist?
Then 23 years old, Douglass conquered his nervousness and gave an eloquent speech about his rough life as a slave.
who did he give the speech to?
Massachusetts Anti-Slavery Society's annual convention in Nantucket.
how was it received?
During this tour, slavery supporters frequently accosted Douglass.
did it receive any praise?
At a lecture in Pendleton, Indiana, an angry mob chased and beat Douglass before a local Quaker family, the Hardys, rescued him.

Question: when did he become a preacher?
Self-contained rewrite: when did Frederick Douglass become a preacher?