WATCH: Band leaves passersby stunned by bringing an 800-year-old Icelandic song back to life

The eclectic Icelandic band Árstíðir is currently touring the United States, but they may be best known for stopping rushing commuters cold in their tracks with a demonstration of ancient Icelandic music.

Five band members sang the Icelandic hymn, Heyr himna smiður, which was written by chieftan Kolbeinn Tumason 1208, reportedly on his deathbed, at the cusp of the most violent and tumultuous time in Icelandic history.

The newly-Christianized region would soon break out in inter-clan warfare and decades after the hymn was written, fall to Norway.

The song is a poem asking for guidance and peace in the face of looming warfare.

Listen to the song, sung acoustically by Árstíðir, here: