the shortest services in the daily cycle of Orthodox worship, which consist of the Trisagion, three psalms, the troparion and kontakion of the day and several additional prayers. First Hour is generally served as part of the All-Night Vigil, immediately after Matins; Third Hour is commonly served before the Divine Liturgy or, if the latter is not served, is read separately, around 9 o'clock in the morning; Sixth Hour is commonly served immediately after Third Hour before Divine Liturgy or, if the latter is not served, is read separately around midday; Ninth Hour is served at approximately 3 p. m. or directly before Vespers. The H. also take on several special forms: the so-called Royal Hours are served on the eves of the Nativity of Christ and the Theophany and Holy Friday, and comprise the First, Third, Sixth, and Ninth Hours in sequence with the addition of readings from Scripture; Lenten Hours, in which some extra prayers are added to the usual format; and Paschal Hours, which are sung before the beginning of the Paschal Divine Liturgy and consist of a number of sung troparia without psalms.
Each day is now divided into 24 equal hours of 60 minutes each. However, in earlier times, time was not so rigid, as discussed below in Hours, Planetary.