Iron Maiden frontman Bruce Dickinson spoke in an interview with Vulture and explained  the real reason he left Iron Maiden in 1991. He said:

“When I left Maiden, I was pretty hard on myself. I said, ‘This whole setup is a limitation. It’s a lovely golden cage that’s comfortable and earns loads of money and I could go on recycling our identity, but I don’t want to do that. The only way I’m gonna find out what’s beyond and grow as a singer is to do something different. And the only way I’m gonna get taken seriously, is to leave.’

I realized when you’re in Iron Maiden, everyone blows smoke up your ass. In the ’80s, when you’re in a big band, you have publicists and all kinds of people to protect you.

As soon as you leave the bubble, everybody goes, ‘You know, I always just wanted to kick that guy in the nuts!’ It’s open season! That’s what happened to me. It was a shock. But, at the same time, I was like, ‘Well, this is why you did it.’ You step outside the box to find out what’s outside the box. You just have to take it on the chin and go, ‘Move on. This is evolution. This is Darwinism. It is survival of the fittest and if you can’t evolve into something that has a useful function, slink away and die.’

You basically throw yourself to the universe and say, ‘Okay, should I really exist as a singer? Is there anything useful I’m bringing to the world by being in a heavy metal band other than nostalgia?’ Because if that’s all it is, maybe I should just take that person and quietly strangle him and go do something more useful instead.

If you want to be an artist, you can’t be resting on your laurels. You’ve got to be out there doing something different. I didn’t know what to do, which is why I left. I think people assumed when I left that I had a plan. Nope. No plan. Which I think the guys in the band found really hard to understand.”

Click here to entire interview.