- For the two-headed dog of mythology, see Orthrus.
In the Eastern Churches, Orthros (Greek (ὄρθρος, meaning "early dawn" or "daybreak") or Oútrenya (Slavonic Оўтреня) is the last of the four night offices, which also include Vespers, Compline, and Midnight Office. In traditional monasteries it is celebrated daily so as to end at sunrise. In parishes it is normally served only on Sundays and feast days. It is sometimes called Matins after the western liturgy it most nearly corresponds to.
Orthros is the longest and most complex of the daily cycle of services. It is normally celebrated in the early morning, sometimes—especially in monasteries—preceded by the Midnight Office, and usually followed by the First Hour. On Great Feasts it is celebrated as part of an All-Night Vigil on the evening before, combined with Vespers and the First Hour. In the Slavic tradition, an All-Night Vigil is served every Sunday (commencing on Saturday evening). In the Greek parish tradition, Orthros is normally served just before the beginning of the Divine Liturgy on Sunday morning.
The akolouth (fixed portion of the service) is composed primarily of psalms and litanies. The sequences (variable parts) of Matins are composed primarily of hymns and Canons from the Octoechos (an eight-tone cycle of hymns for each day of the week, covering eight weeks), and from the Menaion (hymns for each calendar day of the year). During Great Lent, some of the portions from the Octoechos and Menaion are replaced by hymns from the Triodion and during the Paschal Season with material from the Pentecostarion. On Sundays there are also Gospel readings and corresponding hymns from the eleven-part cycle of Resurrectional Gospels.
- All of the psalms used herein are numbered according to the Septuagint, which is the official version of the Old Testament used by the Orthodox Church. To find the corresponding KJV numbering, see the article Kathisma.
- Matins opens with what is called the "Royal Beginning", so called because the psalms (19 and 20) are attributed to King David and speak of the Messiah, the "king of kings"; in former times, the ektenia (litany) also mentioned the Emperor by name. (The Royal Beginning is omitted at All-Night Vigil and also during Paschal season, when it is replaced by the Paschal troparion chanted thrice):
- The priest's opening blessing: Blessed is our God ..., reader: Amen. O Heavenly King ..., and the Trisagion prayers (Note: Heavenly King ... is omitted between Pascha and Pentecost)
- Psalms 19 and 20, during which the priest performs a full censing of the temple (church building and worshippers).
- Glory... Both now... and the Trisagion prayers.
- The Royal Troparia:
- Troparion of the Cross: Save, O Lord, Thy people and bless Thine inheritance, granting unto Orthodox Christians [formerly the Emperor] victory over enemies; and by the power of Thy cross do Thou preserve Thy commonwealth.
- Glory to the Father, and to the Son, and to the Holy Spirit.
- Kontakion of the Cross: O Thou Who was lifted up willingly on the Cross, bestow Thy mercies upon the new community named after Thee, O Christ God; gladden with Thy power the Orthodox Christians, granting them victory over enemies; may they have as Thy help the weapon of peace, the invincible trophy.
- Both now and ever and unto the ages of ages. Amen.
- Theotokion: O awesome intercession that cannot be put to shame, O Good one, disdain not our prayer; O all-hymned Theotokos, establish the commonwealth of the Orthodox, save the Orthodox Christians, and grant unto them victory from heaven, for thou didst bring for God, O thou only blessed one.
- The priest offers a brief litany
- Ekphonesis by the priest: Glory to the holy, consubstantial, life-giving and undivided Trinity, always, now and ever, and unto the ages of ages
- The Six Psalms (3, 37, 62, 87, 102, and 142), during which the priest says twelve silent prayers: six in front of the Holy Table (altar), and six in front of the Holy Doors
- The Litany of Peace (also known as the Great Litany)
- Theos Kyrios ... (God is the Lord ...) and the apolytikion (troparion of the day)
- The Psalter (either two or three sections, depending upon the liturgical season). For each section the following order is followed:
- On Sundays: Evlogetaria (Blessed are you, O Lord, teach me your statutes)
- The Little Litany
- On Sundays and Feast Days:
- The Hypakoë is chanted to prepare for the message of the Gospel reading
- The Anavathmoi ("hymns of ascent") based on Psalms 119-133, called the Song of Degrees)
- The Prokeimenon
- The order of the Matins Gospel is as follows:
- Deacon: Let us pray to the Lord, Choir: Lord, have mercy, and the priest responds with an ekphonesis
- Deacon Let everything that hath breath praise the Lord
- The Gospel is read by the priest
- On Sundays, and every day during Paschal season: Choir: Having beheld the Resurrection of Christ ...
- Psalm 50
- Sundays and Feast Days: Glory ..., both now ... and a hymn
- Sundays, Feast Days and Lenten Days, the petition: O God, save your people and bless your inheritance ..."
- The Canon:
- First and Third Odes
- Little Litany
- Sessional Hymns
- Fourth, Fifth, and Sixth Odes
- Little Litany
- Kontakion and Oikos
- Synaxarion (commemorating the saints of the day)
- Seventh and Eighth Odes
- The Magnificat (My soul doth magnify the Lord ...) while the deacon censes the Church
- Ninth Ode
- Little Litany
- Sundays and certain Feast Days: Holy is the Lord our God, three times
- The Exapostilaria (hymns related to the day's Gospel, or the day's feast)
- The Lauds or Praises (Greek: Ainoi): Psalms 148, 149, 150 - if it is Sunday or a feast day, stichera are interspersed between the final verses
- The ending:
- The Doxastikon (the Glory hymn), when chanted properly is the longest, and usually the richest, hymn of the service. Both the Glory... and Both Now... are chanted.
- Sundays and Feast Days: the Great Doxology is chanted, followed by the apolytikion, the two litanies and the Dismissal
- Weekdays: the Small Doxology is read, followed by the first litany, the Aposticha, It is good to give praise unto the Lord..., the Trisagion sequence followed by the apolytikion, and the second litany (there is no dismissal)
- The First Hour
In very traditional monasteries, readings from the Church Fathers can be added after each of the Sessional Hymns.
Types of Orthros 
There are seven types of Matins:
Basic Forms 
- Sunday Orthros—The longest of the regular orthros services - Gospel Reading and Great Doxology. If this service is celebrated in its entirety it can last up to three hours. As a result, in most practical situations, abbreviations are made.
- Daily Orthros—Celebrated on most weekdays - No Gospel reading, Small Doxology.
- Feast-day Orthros—Very similar to Sunday Orthros, excluding those parts which are strictly Resurrectional in nature - Gospel reading and Great Doxology.
Special Forms 
- Lenten Orthros—Weekdays (Monday through Friday) during Great Lent, and certain days during the lesser fasting seasons (Nativity Fast, Apostles' Fast and Dormition Fast). The service follows the order of Daily Orthros but with penitential material added (hymns and prayers), most days have three kathismas from the Psalter, "God is the Lord" is replaced by "Alleluia" (from which fact these days are called "days with Alleluia"). The petition: "O God, save your people and bless your inheritance ..." is read by the priest. There is no Gospel reading. At the canon the Biblical Odes are read, the Small Doxology is read. Special Lenten ending of the service, including the Prayer of St. Ephraim.
- Great and Holy Friday Orthros—Twelve Passion Gospels are interspersed throughout the service; Antiphons are used between the Gospels (these originated in a different office); While the troparion at the 15th antiphon Today is hung upon the cross... (Simeron krematai) is chanted, the priest brings a large crucifix into the center of the church, and all venerate the cross. The Beatitudes are chanted with special stichera. Small Doxology.
- Great and Holy Saturday Orthros—Lamentations are chanted around the epitaphios, interspersed between the verses of Psalm 118. Contains some elements of the old cathedral office: procession with epitaphios, reading of three pericopes (lessons from the Old Testament, epistle and Gospel) at the end - Great Doxology.
- Paschal Orthros—Celebrated during Bright Week, from the Sunday of Pascha (Easter) until Thomas Sunday. The service is completely different from the rest of the year; only the Ektenias, Canon and Lauds are the same; everything else, including the psalms, are replaced by special Paschal hymns. The Priest vests fully in his Eucharistic Vestments on the Sunday of Pascha, and in Epitrachelion (Stole) and Phelonion (chasuble) for the other days of Bright Week - Gospel only on Sunday, no Doxology at all (neither Small nor Great).
See also 
- Liturgy of the Hours
- Canonical hours
- Anglican Morning Prayers
- Night Hours
- Book of Hours
- Matins in Lutheranism
- One of the oldest elements in the orthos service and according to a pious tradition said to recall the Last Judgement, as Psalm 104 at Vespers recalls the Creation.