What did led zeppelin sing about?

Answer 1

Jack Black said that they sang about vikings, having sex and vikings having sex. The Great Robert Plant's lyrics often had references to things like the vikings, fantasy type stuff (such as The Lord of the Rings) and due primarily perhaps to the fact that they always covered old blues songs, messed up relationships. A lot of the songs where they talk about stuff like that (messed up relationships) were covers but some where their own.

Answer 2

The songwriters have never discussed what it is about, but the lyrics suggest it's saying that no matter how tough things get, in the light you will find your way.