[4] The origin of Terce, like that of Sext and None, to which it bears a close relationship, dates back to Apostolic times.
According to an ancient custom of the Romans and Greeks, the day and night respectively were divided into four parts of about three hours each.
[5] The Fathers of the Church and the ecclesiastical writers of the third century frequently mention Terce, Sext, and None as hours for daily prayers.
[5] Tertullian, around the year 200, recommended, in addition to the obligatory morning and evening prayers, the use of the third, sixth and ninth hours of daylight to remind oneself to pray.
In the fourth century the custom of praying at these hours became more frequent, and even obligatory, at least for monks.
The elements of the prayer of Terce, Sext, or None before the fourth century probably consisted of psalms, canticles, hymns, and litanies.
"[8] Sources from the fourth century onwards offer a more precise picture of the composition of the hour of Terce.
[9] This was also the view held in Ireland, where the psalms selected for Terce focused on the glorification of the risen Christ.
On Sundays, Terce was sung in organum before the principal Mass, and included the hymn Nunc sancte nobis spiritus, which recalls the descent of the Holy Ghost upon the Apostles.
[12] The custom of Little Hours grew up in the monastic and larger Church in the course of the centuries and still is followed in stricter monasteries and hermitages.
These are followed by a short reading from Scripture, once referred to as a "little chapter" (capitulum), and by a versicle and response.
Our Father..." In the Eastern Orthodox and Greek Catholic Churches, the office of the Third Hour is normally read by a single Reader and has very little variation in it.
During Holy Week, on Great Monday, Tuesday and Wednesday, the services are similar to those during Great Lent (including the reading of a kathisma), but instead of the normal Lenten hymns which replace the Kontakion, the Kontakion of the day (i.e., that day of Holy Week) is chanted.