Oktōēchos or Octoechos is the name of the eight mode system used for the composition of religious chant in most Christian churches during the Middle Ages. In a modified form, the octoechos is still re
Intonation according to Erotapokriseis and standard intonation of echos protos: "You descend 4 steps [φοναὶ] from the echos protos [kyrios protos/authentic protus] and you will find again the plagios protos, this way"
Intonation according to Erotapokriseis and standard intonation of echos devteros: "You do the same way in echos devteros. If you descend 4 steps to find its plagios, i.e. πλ β', thus"
The earliest tonary: the fragment of Saint-Riquier in the Psalter of Charlemagne (F-Pn lat. Ms. 13159, fol. 167r)
The intonation formulas for the 8 tones according to the Aquitanian tonary of Adémar de Chabannes (F-Pn lat. Ms. 909, fol. 251r-254r)
Phthora nenano 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. The phthorai nenano and nana were favoured by compos
Hagiopolitan Octoechos
…tetartos were bridged by the enharmonic phthora nana, and changes between the echos protos and the echos plagios devteros by the chromatic phthora nenano. Nevertheless, the terminology of the Hagiopolites somehow suggested that nenano and nana as phthorai "destroy" one or two diatonic degrees used within…
List of 7 phthorai used for transposition in a 17th-century Papadike (GB-Lbl Ms. Harley 5544, f. 5v).
"ἡ σοφωτάτη παραλλαγὴ κυρίου Ἰωάννου Ἰερέως τοῦ Πλουσιαδηνοῦ" in an 18th-century manuscript (Athos, Docheiariou monastery, Ms. 319, fol. 18v)
Chrysanthos' exegesis of the medieval apechema of phthora nenano (Chrysanthos 1832, 142—§317)
The medieval enechema of the diatonic echos plagios devteros (Chrysanthos 1832, 139)