Britney didn't have an 'era' in the traditional sense, she just slayed from 1999-2005 non-stop. She was everywhere and that part of her career was basically one huge untouchable era/historical period which ended careers, scored global hits and cemented herself as pop royalty. The fact the GP still remember britney slaying in that period, fresh in their mind with all the visuals etc to this very day proved how big she was.
