Orthrōs

(Gk. "dawn")

   The principal morning divine office in the Byzantine rite. Taking shape as early as the fifth century, monastics began to add the singing of stichēra and kanon in the sixth. The parts of the orthrōs are: troparia; hexapsalmos, selections from six psalms; Theos kyrios; usually an excerpt of Psalm 117 with verse 27 used as a refrain; polyeleos, verses from Psalms 134–135; {}amōmos, Psalm 118; anabathmoi, three or four troparia; prokeimenon, a responsorial chant of selected psalm verses; pentēkostos, Psalm 50, sung antiphonally with concluding stichēron or troparion on important feasts; kanōn; kontakion; exposteilarion, a short chant; {}hoi ainoi, Psalms 148–150, sung on Sundays and feasts; heōthinon, an elaborate stichëron of 11 chants on Resurrection themes; Doxa en hypsistois, the major doxology; and trisagion.