Conversation so far:
When was the first boy band?
The earliest forerunner of boy band music began in the late 19th century as a cappella barbershop quartets.
When did they become popular?
The term boy band was not established until the late 1980s as before that they were called male vocal groups or "hep harmony singing groups".
Who was the first major boy band group?
The Liverpool quartet known as The Beatles were not only the quintessential rock band.
What were some other early boy bands?
The Monkees, which spawned the music group of the same name, formed by the four starring actors.

Question: How did the boy band evolve over the years?
Self-contained rewrite: How did the boy band evolve over the years?