For the last 100 years or so, it has been pretty easy to explore and chart the ups and downs of popular music. In medieval times, however, it wasn't so easy. Enter Corvus Corax, a German outfit that played exclusively dark-ages-era "pop" (for lack of a better word) -- the band was focusing less on the church music which dominated the era, and more on rural folk tunes -- with authentic instruments and period costumes.