a time in the past when someone or something was very successful.
The book focusses on the glory days of the jazz scene in the early 1940's and 1950's.
glory days
The most successful time that someone or something has experienced; a past period of better times. My uncle used to play professional baseball, but he suffered a serious injury, and now just likes to relive the glory days of his career.Disco's glory days are far behind us, thank goodness.Back in the glory days, we could sell this place out four nights in a row.