Exhorder is an American thrash/groove metal band from New Orleans, Louisiana. They are credited as the purveyors of the groove-oriented thrash sound later made famous by bands such as Pantera, White Zombie, and Machine Head. Initially active from 1985 to 1992, they have since reformed in 2008. Exhorder was formed in 1985 in New Orleans, Louisiana. After releasing several demos in the vein of pure thrash metal, they started to adapt more of a groove metal-oriented sound with their debut studio album, Slaughter in the Vatican, released in 1990.