Nenano

Phthora nenano (Medieval Greek: φθορὰ νενανῶ, also νενανὼ) is the name of one of the two "extra" modes in the Byzantine Octoechos—an eight-mode system, which was proclaimed by a synod of 792 (792). The phthorai nenano and nana were favoured by composers at the Monastery Agios Sabas, near Jerusalem, while hymnographers at the Stoudiou-Monastery obviously preferred the diatonic mele.

The phthora nenano as part of the Hagiopolitan octoechos

Today the system of eight diatonic modes and two phthorai ("destroyers") is regarded as the modal system of Byzantine chant, and during the eighth century it became also model for the Latin tonaries—introductions into a proper diatonic eight mode system and its psalmody, created by Frankish cantores during the Carolinigian reform. While φθορά νενανῶ was often called "chromatic", the second phthora was named "nana" (gr. φθορά νανὰ) and called "enharmonic", the names were simply taken from the syllables used for the intonation (enechema). The two phthorai were regarded as two proper modes, but also used as transposition or alteration signs. Within the diatonic modes of the octoechos they cause a change into another (chromatic or enharmonic) genus (metavoli kata genos).

The earliest description of phthora nenano and of the eight mode system (octoechos) can be found in the Hagiopolites treatise which is known in a complete form through a fourteenth-century manuscript. The treatise itself can be dated back to the ninth century, when it introduced the book of tropologion, a collection of troparic and heirmologic hymns which was ordered according to the eight-week cycle of the octoechos. The first paragraph of the treatise maintains, that it was written by John of Damascus.