The
“nomoi
” are related to the
“automela troparia
” of Byzantine music. On the melody of the
“automela
” were sung numerous other chants, called
“prosomoia
”. Corresponding phenomena exist in the folk music of modern Greece, especially on the island of Crete. Related to the more developed phase of the use of
“nomoi
” are the Byzantine
“echoi
” (modes) as well as certain practices in the folk music of Epirus.
Akin to the
“echoi
” and the
“nomoi
” in concept are the
“ragas
” of classical Indian music. Here too, elaborate and complex compositions are based on a kind of improvisation, limited by the strict rules of the
“ragas
”.