Conversation so far:
How long before Sarah Vaughan joined the other group of musicians?
During her week of performances at the Apollo Theatre, Sarah Vaughan met Earl Hines. After a tryout, Hines replaced his female singer with Vaughan on April 4, 1943.
What year did Billy Eckstine quit the Earl Hines Band?
Billy Eckstine quit the Earl Hines band in late 1943 and formed a big band with Dizzy Gillespie.

Question: What era of music was all this in?
Self-contained rewrite: What era of music was Sarah Vaughan in?