Rattlehead
Member
The early period is with Paul Dianno on vocals. The second period is when Dickinson joined and Maiden had a huge breakthrough with The number of the beast. The 3rd period you can call the dark years because heavy metal suffered from rising popularity of other genres such as grunge and deathmetal. The last era is the rejunion with Dickinson. (Idont know exact years when they changed singers.)