Taken from their official website:

Svartsot began in early 2005 after the band's precursor, a folk/black metal band in Randers called 'Skoll', came up with an idea for a song called Svartsot (meaning black sickness). As Frederiksen had also begun writing melodies which were leaning away from the black metal-formula, the genre changed to folk metal, and Svartsot was born. It was decided at this point that all lyrics would be in Danish, and that they would be about the history and folk-lore of Denmark.

A selection of new songs were compiled in this vein whilst some older Skoll songs, including the legendary Jotunheimsfærden, were updated to the new style and two demo CD's were produced: Svundne Tider in late 2005 and Tvende Ravne in 2006. The latter attracted the attention of Napalm Records, who signed the band early in 2007.
In July 2007 the band entered the studio of Jacob Hansen to record the first album, 'Ravnenes Saga' (The Saga of the Ravens). The album was well received and through 2008 the band set about touring with the likes of Tyr and Alestorm to promote the album.

As material was being compiled for the second album, cracks began to appear within the band and following, amongst other things, an argument over whether one particular song should appear on the next release, all the band members, excepting Frederiksen, decided to leave. However, they had not counted on his resolve to continue, and he duly recruited new members in the big-line-up-change-of-2009 saga. This 'new' Svartsot was rehearsed and ready to go without having to cancel a single show. However, as Frederiksen had been the main songwriter and lyricist, none of the essence of the music was lost.

Material co-written by members of the pre-split line-up was duly scrapped for the follow-up album, and a selection of new songs were written, with Atkin coming in on lyric co-writing duties. Some older songs, which had previously been left out as certain ex-members were not able to play them, were once again taken up and duly recorded.
The band re-entered the studio in 2009, this time the studio of Lasse Lammert's in Lübeck (Germany), and 'Mulmets Viser' (Songs of the Darkness) was created. The music evolved into a more complex beast, with more instruments, harmonies and tasty melodies than ever before.

A large number of shows and small touring opportunities followed throughout Europe in 2010, the high point being a performance at Wacken 2010, in front of more people than we had ever seen.
Frederiksen and Atkin then began writing material for album no. 3, a darker and more medieval inspired work on the outbreak of the Black Death in 1349. The song-writing evolved further in the direction of the later songs written for Mulmets, becoming again more complex, with more instruments, more lead and harmony parts, and much to Bager's dismay, even more lyrics! Having felt we had 'done the Viking thing', and trying to separate ourselves from a hundred other 'Viking' themed bands, we consciously brought the style of music and lyrical themes into the early medieval period, while still retaining our trademark melodies, heavy drinking songs and 'hey-ho's' for it still to be recognisable as ourselves.

'maledictus eris' (Cursed shalt thou be) was released in the summer of 2011 – hardly anyone noticed it wasn't about Vikings – and we duly set about touring throughout Denmark, with a couple of stops in Germany, and an amazing couple of shows in Russia with Korpiklaani. Between October 2010 and now, a few minor line-up changes have taken place, although the song-writing core of Cris Frederiksen and James Atkin, vocalist Thor Bager, and 'folk-guy' Hans-Jørgen Martinus Hansen have remained constant since 2009. Each change seems to have improved our line-up musically, and brought, incredibly, ever larger beards into the Svartsot fold!

Work is currently underway to a follow-up for 'maledictus eris', with further evolution of the music and lyrics continuing all the time. All being well, we should return to the studio some time in 2013 to record it. Until then, we look forward to seeing you on the road, beer in hand! (or if you can't make it, at least contributing to one of our infamous Facebook discussions!)

You can read the whole biography here