text of the fourth Council of Carthage to prove that it existed in the
fourth century, _Clericus, qui absque corpusculi sui inequalitate
vigiliis deest, stipendiis privatus, excommunicatur_. Gavantus can find
traces of it only as late as the sixth century. Several decrees of
provincial councils regarding this custom are quoted by writers on
liturgy. However, the matter is clearly and definitely dealt with by the
General Council of Lateran (1213) and by the Bulls, _Quod a nobis_ and
_Ex proximo_, of Pope Pius V. (1571). This Pope expressly states that
wilful omission of the Divine Office is a grave sin--"_grave peccatum
intelligat se commissise_."

The obligation of reciting the office binds those in Holy Orders, even
though they may be excommunicated, suspended, degraded or imprisoned.
The obligation binds for the first time when subdeaconship has been
conferred. Subdeacons are bound to recite "the hour" in the office of
the day, corresponding to the time of their ordination. If the
ordination is finished before nine o'clock, the sub-deacon is bound to
begin his recitation with Terce. If the ordination is held between nine
o'clock and mid-day the recitation begins with Sext. The question is
discussed by theologians if the recitation of Terce or Sext may be
lawfully and validly made before the ordination. Some authors deny that
it may be justly and lawfully done, while others, with some probability,
affirm that before ordination the debt may be paid in advance.

Are priests bound to follow the Proper in their own diocese?

They are, if it has been approved by the Sacred Congregation of Rites
(S.R.C., 4597-4746). But a priest travelling (_peregrinus_) should
recite the office according to the calendar of the church to which he is
attached regularly, but the obligation of following the calendar of his