There is more than one group with this name:

http://www.arcusband.com/

Pop-rock band from Ljubljana, Slovenia. The sound is influenced by many music ganres but they still maintain their own fusion of rock, pop and other styles.

or

http://www.arcusmusic.cz

Arcus was founded in 1997 as a primarily Renaissance music group. Later Arcus moved onto Gothic music which mandated their choice of instrument. Currently the group is going through next evolution, new songs and ballads are more and more modern but still with the medieval roots. Arcus have participated in many medieval events both in the Czech Republic and abroad, for example in Austria, Germany, Luxemburg, Denmark and or in Italia.

For a year now the group has had six members. They draw a material from all corners of Europe focusing particularly on secular music of the twelfth through fifteenth century. Arcus have also own songs and ballads in repertory.

The group is especially sought after to perform at medieval markets thanks to its volume and rough contemporary rawness. Arcus also have a lot of experiences of participating in individual gigs on the big stages. Naturally, Arcus performs wearing period costumes.

User-contributed text is available under the Creative Commons By-SA License and may also be available under the GNU FDL.