[cperkins]

A very important aspect that Parry and Murko uncovered is that _music_ was the thing that helped them memorize these incredibly long works. The guslari played a one string "gusle" (iirc) and recited the work along with a song.

Some of the guslari bards could not perform the recitation without their instrument.

And, fwiw, I recall that some assert that the guslari bards were all illiterate. It has been asserted (not by me) that literacy interferes with the guslari activity of memorizing and replaying enormous epics.

Check out Ted Goia "A Subversive History of Music" for an overview - but there is a lot of other scholarship on this.