While hard rock influences were still present, such as on "Immigrant Song", acoustic-based songs such as "Gallows Pole" and "That's the Way" showed Led Zeppelin were capable of playing different styles successfully. The band wrote most of the material themselves, but as with prior records, included two songs that were re-interpretations of earlier works: "Gallows Pole", based on a traditional English folk song, by way of American singer Fred Gerlach; and "Hats Off to (Roy) Harper", a reworking of a blues song by Bukka White.