Dubbed "Viking metal" thanks to pervasive lyrics about Norse mythology in their early days, Enslaved were started in 1991 by Norwegian teenagers Ivar Bjornson and Grutle Kjellson (ages 13 and 17, respectively, at the time). Their first release, an EP split with Emperor, appeared in 1993, with their full-length debut, Vikingligr Veldi, following a year later. From the start, the band was prone to complex, multisectional epics that often stretched beyond the 10-minute mark and demonstrated a different approach to the black metal scene emerging around them. Keyboards, mouth harps and a decidedly more sophisticated recording setup than that of most of their almost-lo-fi counterparts set Enslaved apart from the pack and gave rise to notions of progressive black metal. These elements grew more distinct, even replacing traditional black metal moves according to some, as the band continued to release records into the '00s (Vertebrae, a straight-up prog metal album save the vocals, came out in 2008). Today Enslaved are cited as a major influence on countless metal acts.