AFAIK the dominant theory is that they weren't memorized as a whole text, but composed on the fly with the help of a memorized set of stock formulas. [0] [0]:

AFAIK the dominant theory is that they weren't memorized as a whole text, but composed on the fly with the help of a memorized set of stock formulas. [0] [0]: https://poets.org/glossary/oral-formulaic-method https://poets.org/glossary/oral-formulaic-method