response: The bands have a number of influences. Music such as those of the blues, folk, and psychedelia.
original_response: I think so.  Zeppelin is unique in that is has a lot of blues, folk music, and psychedelia in their music.
history: I have a new girlfriend who's really into heavy metal music, so I need a quick crash course. Good bands, brief history, that kind of thing. OK, well heavy metal, also known as just metal, began in the 1960s and 70s in the United Kingdom How is that possible? People from the UK just seem so...harmless! Ha.  Looks can be decieving.  In 1968 three major metal bands formed:  Black Sabbath, Deep Purple, and Led Zeppelin. I've definitely heard of the first and third from that list, but I've never really thought of Led Zeppelin as heavy metal. Will she buy it if I mention them?
knowledge: Their style drew from a wide variety of influences, including blues, psychedelia, and folk music.