"Mine eyes woke before the morning that I might meditate on Thy sayings." Orthros (Greek for "Morning"), also called "Matins" (Latin for "Morning"), is the service of Morning Prayer, often offered immediately before the Divine Liturgy, but also able to stand alone. Like Vespers, Orthros dates back to the Early Church, and, also like Vespers, the modern form of Orthros has its origin in the Mar Saba Monastery. Orthros typically has three forms: Sunday Orthros, served on Sunday Mornings; the very similar Festal Orthros, served for important Saints, Feasts, and Commemorations during the week; and the simpler Daily Orthros.
Orthros begins with a censing of the whole Church, while the chanters recite prayers and hymns. This is followed by a litany as the Priest censes around the altar table, ending with the praise, "Glory to the Holy, Consubstantial, Life-giving and Undivided Trinity, always, now and ever, and unto ages of ages." The chanter then begins the reading of the Six Psalms or Hexapsalmos (Psalms 3*, 37, 62, 87, 102, and 142). It is said that the time it takes for those psalms to be read is the full amount of time Christ will need to judge Humanity on the Last Day. As these are being read, the priest quietly reads twelve preparatory prayers. This is followed by the petitions of the Great Litany with the response "Lord, have mercy." After the Litany, the chanters sing the hymn "God is the Lord..." interspersed with psalm verses and followed by hymns in honor of the Saint, Feast, or Commemoration of the day. Following those hymns, the priest intones a Small Litany, which is itself followed by a series of hymns and psalms, which differ depending on the day and rank of Feast.
At Sunday and Festal Orthros, following several psalm verses, there is a reading from the Holy Gospel. On Sundays this is called the "Eothinon Gospel," and recounts one of the Lord Jesus' appearances after His Resurrection. At Festal Orthros the Gospel reading is for the Saint or Feast, and either recounts the event or gives a teaching related the the Saint's life. After the reading, the chanters then read Psalm 50 and sing hymns asking for the intercessions of the Virgin Mary and the Saints. The priest (or deacon) then reads aloud a long intercessory prayer, asking for all the saints (many of them by name) to pray for the Christian people. This is followed by the reading of two more hymns, and of the Synaxarion: a short life of the Saint commemorated that day. This is followed by still more hymns, most prominently the singing of the Magnificat, the song of the Virgin Mary from Luke 1:46-55. Then two more hymns are sung, followed by the Psalms of Praise (Psalms 148, 149, and 150), which at Sunday and Festal Orthros are sung interspersed with hymns to the Saint, Feast, or Commemoration, but in Daily Orthros are simply read with no extra hymns.
Finally, on Sundays and Feast Days, if the Divine Liturgy is served afterwards, Orthros concludes with the Great Doxology, and extended hymn of praise based on the the song of the Angels heard by the Shepherds on Christmas Day, "Glory to God in the Highest, and on earth peace, goodwill among men." This leads directly into the beginning of the Divine Liturgy. At Daily Orthros, the service is concluded with more a few more hymns and litanies, finally ending with the priest's dismissal prayers and blessing.
*Psalms are numbered according to the Greek Septuagint