Before he made his first speech defending the South, Secretary of State John C. Calhoun advised him to hold back a little, but Yancey gave a brilliant and forceful opening address that gave him instant national fame. He was actually challenged to a duel because of the speech, but the dispute was settled before any shots were fired.
Mr. Yancey served two terms in Congress then came back to Alabama to practice law in Montgomery. ( One old biography said he came back because he needed to "repair his fortune" which is a nice way of saying he was running out of money. )
Mr. Yancey's ability to stir up the crowds in his speeches earned him the reputation and nickname of being a "fire eater." He was the leader of the Alabama delegation to the Democratic National Convention in Charleston, where he led a walk out of Southern delegates which split the party and basically guaranteed the election of Abraham Lincoln, the Republican, as President in 1860.
Jefferson Davis was then elected President of the Confederate States and he offered Mr. Yancey any government position that he might desire. Mr. Yancey asked to be appointed Minister to Great Britain, and his request was granted. After a year he returned to Alabama. He died near Montgomery in the summer of 1863.
Here is an original photograph I have of William L. Yancey.