Formed in 1989 as a Western-themed bluegrass band, the Dixie Chicks later became one of the most popular acts in contemporary country music, as well as the highest-selling female group of all time. Beginning with 1998's Wide Open Spaces, they struck a balance between the commercial, radio-ready aesthetic of country-pop and the rootsy flair of neo-traditionalist country, a combination that helped distinguish the trio from such concurrent stars as Shania Twain. The Dixie Chicks further distanced themselves from country's conservative boundaries as their career progressed, although their outspoken beliefs -- specifically Natalie Maines' open criticism of the war in Iraq, which ignited a backlash in 2003 -- were sometimes exercised to the detriment of the band's sales.