Pagan metal is heavy metal music that fuses extreme metal with "the pre-Christian traditions of a specific culture or region through thematic concept, rustic melodies, unusual instruments or archaic languages", usually referring to folk metal or black metal. The Norwegian band In the Woods... was one of the first bands commonly viewed as pagan metal. Metal Hammer author Marc Halupczok wrote that Primordial's song "To Enter Pagan" from the band's demo "Dark Romanticism" contributed to defining the genre. Pagan metal bands are often associated with Viking metal and folk metal. Bands such as Moonsorrow and Kampfar have been identified as fitting within all three of those genres.