Nana (echos)

Phthora nana (Medieval Greek φθορά νανὰ) is one of the ten modes of the Hagiopolitan Octoechos consisting of 8 diatonic echoi and two additional phthorai. It is used in different traditions of Orthodox chant until today (→ Neobyzantine Octoechos). The name "nana" is taken from the syllables (written in ligatures "ʅʅ") sung during the intonation which precedes a melody composed in this mode. The name "phthora" derived from the verb φθείρω and means "destroy" or "corrupt". It was usually referred to the diatonic genus of the eight mode system and as a sign used in Byzantine chant notation it indicated a "change to another genus" (μεταβολὴ κατὰ γένος), in the particular case of phthora nana a change to the enharmonic genus. Today the "nana" intonation has become the standard name of the third authentic mode which is called "echos tritos" (ἦχος τρίτος) in Greek and "third glas" (третий Гласъ) in Old Church Slavonic.

In the theory and notation of Byzantine and Orthodox chant nana is the name of a special phthora which had been used in different ways according to its historic context:

It is supposed that the Hagiopolites treatise served during the 9th century as a manual preceding a chant book called tropologion. The book contained a collection of simple hymns troparia as well as heirmoi which served as melodic models (μέλοι) for the 10 modes of Octoechos.

Nana holds the status one of the two "special" additional echoi or "mesoi" (medial forms between authentic and plagal echoi) in the system of the Hagiopolitan Octoechos. The other one is called nenano. Already in the Hagiopolites treatise the phthorai nana and nenano have been characterized as both echoi and "not echoi, but phthorai" (→ phthora). This means that they were proper modes with their own models, but they had to be integrated within the Octoechos and its eight-week cycle. Thus, phthora nana was subordinated to the tetartos, and the treatise also referred to it as "Mesos tetartos": as a third medial mode of the tetartos which was neither authentic (kyrios) nor plagal (plagios).

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