This form of office is of great antiquity, going back to the fifth century. In the early ages of the Church and down to the fourteenth century the simple office consisted of the ferial office with lessons, antiphons and prayers. But in the end of the fourteenth century, simples came to be celebrated in the same manner as semi-doubles, with nine lessons and their nocturns, and in case of occurrence were transferred. As a result the offices of Sunday and the ferial offices were practically crushed out of the Breviary. The Commission of Reform applied an easy remedy, by restoring simple feasts to their ancient place and status. Now, they are not to be transferred; but in case of occurrence with a feast of higher rite they are merely commemorated.
These feasts have first Vespers only. At Matins, the nine psalms and three lessons are said as one nocturn. The psalms in semi-double feasts are from the Psalter under the day of the week on which the feast is celebrated. “In quolibet alio Festo duplici etiam major, vel semi duplici vel simplici et in Feriis Tempore Paschali, semper dicantur Psalmi, cum antiphonis in omnibus Horis, et versibus ad matutinum, ut in Psalterio de occurrente hebdomadae die” (Tit, I. sec, 3. Additiones et Variationes).
In commemorations in the Office, the versicle, response, antiphon and collect of a semi-double is made after the following commemorations (if they should have a place in the recitation of the day).
(1) Any Sunday, (2) a day within the privileged octave of the Epiphany or Corpus Christi, (3) an octave day, (4) a great double, (5) a lesser double. Of course the first commemoration is always of the concurring office except it be a day within a non-privileged octave, or a simple. In reckoning the order of precedence between feasts which occur on the same day, lists given in The New Psalter and its Use, p. 108, show that thirteen grades of feast stand before the feasts of semi-double rite. And in the order of precedence as to Vespers, between feasts which are in occurrence, these feasts stand in the eleventh place, being preceded by (1) doubles of the first class of the universal Church, (2) lesser doubles.
We translate the Latin Dies Dominica by our word Sunday, for in English the days of the week have retained the names given to them in Pagan times. In Irish, too, Deluain, Monday, moon’s day, shows Pagan origin of names of week days.
The literal translation of the Latin Dies Dominica, the Lord’s Day, is not found in the name given to the first day of the week in any European tongue, save Portuguese, where the days of the week hold the old Catholic names, domingo, secunda feira, terca feira, etc. It is said that the seven days of the week as they stand in numerical order were retained and confirmed by Pope Silvester I. (314-336): “Sabbati et Dominici diei nomine retento, reliquos hebdomadae dies Feriarum nomine distinctos, ut jam ante in Ecclesia vocari coeperunt appellari voluit; quo significaretur quotidie clericos, abjecta caeterarum rerum cura, uni Deo prorsus vocare debere” (Brev. Rom. in VI. lect. St. Silvester Pope; 31st Dec.).