Outlaw country is a subgenre of country music, most popular during the late 1960s and the 1970s (and even into the 1980s in some cases), sometimes referred to as the outlaw movement or simply outlaw music. The focus of the movement has been on "outlaws", such as Johnny Cash, Waylon Jennings, Merle Haggard, Willie Nelson, Kris Kristofferson, and Hank Williams Jr. Other associated artists include David Allan Coe, the Eli Radish Band, Leon Russell, Townes Van Zandt, Billy Joe Shaver, Steve Earle, and Gary Stewart. The reason for the movement has been attributed to a reaction to the Nashville sound, developed by record producers like Chet Atkins who softened the raw honky tonk sound that was predominant in the music of performers like Jimmie Rodgers, and his successors such as Hank Williams, George Jones and Lefty Frizzell. According to Aaron Fox, "the fundamental opposition between law-and-order authoritarianism and the image of 'outlaw' authenticity... has structured country's discourse of masculinity since the days of Jimmie Rodgers."