According to Giraldus Cambrensis, Denmark and Norway were two of the most important and influential centres for the dissemination of vocal polyphony throughout medieval northern Europe from Scandinavia to Iceland. Unfortunately, there is almost no other information on this topic from subsequent centuries. Although, interestingly, “The building blocks of Norwegian music – augmented fourth, parallel fifths and octaves, pedal points, asymmetrical rhythms”  has some remarkable similarity with the main features of the singing traditions of twisongur polyphony from Iceland (see above). Considering the deep ethnic and cultural connections between Iceland and Norwegians, this is hardly surprising.