The first wave of black metal emerged in the 80s with bands such as Venom, Bathory and Hellhammer. This initial wave focused on combing a faster paced music with occult, paganistic imagery as introduced by Black Sabbath, whilst still maintaining a dark, brooding atmosphere. In the early 1990s, a second wave resulted from a slew of Norwegian bands (Mayhem, Emperor, Burzum) aiming to push the limits of extreme music. The riffs became fiercer, and the bands became more dedicated to the occultist theme. In some cases, this dedication to brutality extended beyond the music and led to infamous events such as Christian church burnings and even murders.