Anthropologist Sam Dunn traced the origins of power metal back to the late 1970s, when the groundwork for power metal lyrical style was laid down by Ronnie James Dio. The fantasy-oriented lyrics he wrote for Rainbow, concentrated around medieval, renaissance, folk, and science fiction themes, directly influenced modern power metal bands. It is mentioned that songs "Stargazer" and "A Light in the Black", from the 1976 album "Rising" and 1978's "Long Live Rock 'n' Roll", "Kill the King" and "Lady of the Lake", respectively, might be among the earliest examples of power metal. In his 2011 documentary series "Metal Evolution", Dunn further explained how Rob Halford of Judas Priest created a blueprint for power metal vocal delivery. His almost constant high-pitched singing became one of the main characteristics of power metal. The twin-guitar sound promoted by duo of K. K. Downing and Glenn Tipton highly influenced this subgenre. Another pioneer in the power metal genre is Jon Mikl Thor, who was a strong inspiration to the American band Manowar.