A discipline is a law the Church makes with real authority and can, for good reason, change. It binds while it is in force — but it binds because the Church binds it, not because it was revealed, and it is owed obedience rather than the assent of faith.
Each entry below leads with what actually binds today, and then shows a dated timeline of how the rule has moved. The timeline is the teaching: watching a law change is the fastest way to learn it was never dogma. That is not a scandal — it is the Church using an authority Christ gave her. Knowing which rules can move is what keeps a person from panicking when one does, or from treating a custom as though the faith depended on it.
Fasting and Penance
What the Church asks of the body, and how much of it has changed in living memory.
Friday Penance
5 changesEvery Friday is a day of penance — the form is what changed, not the day
All Fridays of the year remain days of penance in the universal law. What changed in 1966 was that bishops' conferences were permitted to let other forms of penance be substituted for abstinence from meat outside Lent — which most of the English-speaking world did, and which a great many Catholics heard as the abolition of the obligation itself.
The Lenten Fast
4 changesTwo days of fasting, six Fridays of abstinence — and it used to be very much more
In the current law, Catholics fast on Ash Wednesday and Good Friday and abstain from meat on those days and on all the Fridays of Lent. Within living memory the Lenten fast bound every weekday of Lent, and before that it was stricter still.
The Eucharistic Fast
5 changesOne hour before Communion — and it was from midnight within living memory
Before receiving Holy Communion a Catholic abstains from all food and drink except water and medicine for one hour. That hour was, until 1953, a fast from the previous midnight — which is the single clearest example on this site of a discipline moving.
The Liturgy and the Sacraments
How Mass is celebrated and how the sacraments are received — the rules, not the realities.
Holy Days of Obligation
4 changesTen in the universal law, six or two or none where you live
Canon law lists ten holy days of obligation besides Sundays, and in the same breath allows bishops' conferences, with Rome's approval, to suppress them or move them to a Sunday. Which is why a Catholic crossing a border can find an obligation appear or vanish.
The Language of the Liturgy
6 changesLatin is still the Church's own language — and the vernacular is not a concession
The Second Vatican Council directed that the use of Latin be preserved in the Latin rites, and in the same document opened the door to the vernacular. What followed went considerably further than the text on the page — a gap that has shaped every argument about the liturgy since.
How Communion Is Received
5 changesIn the hand or on the tongue, kneeling or standing, one species or two
Every question about the manner of receiving Communion — hand or tongue, kneeling or standing, the chalice or not — is disciplinary, has been answered differently in different centuries, and is currently answered differently in different countries.
The Age of First Communion
4 changesAbout seven — and it was twelve or fourteen until 1910
Children are admitted to Holy Communion when they reach the age of discretion, ordinarily about seven, and know Christ from ordinary bread. Before the decree of 1910, most Catholic children waited until twelve or older, and many until they were nearly adult.
The Life of the Clergy
Celibacy in the Latin Church — a discipline, and the Church has always said so.
Law, Books, and Burial
Rules the Church has made, kept, reformed, and in some cases abolished outright.
Cremation and Burial
4 changesForbidden in 1886, permitted in 1963 — and the reason for both is the same
The Church earnestly recommends burial of the body, and permits cremation unless it is chosen for reasons contrary to Christian teaching. Ashes must be kept in a sacred place — not scattered, divided, or kept at home.
The Index of Forbidden Books
5 changesFour centuries of ecclesiastical law, abolished outright in 1966
The Index Librorum Prohibitorum listed books Catholics were forbidden to read without permission. It was formally abolished in 1966 and no longer has the force of ecclesiastical law — the plainest case in the whole section of a discipline being ended rather than adjusted.
The Discipline of Indulgences
5 changesThe doctrine stands; the abuse was condemned by the same council that defined it
That the Church can remit temporal punishment from the treasury of merit is doctrine. Everything about how indulgences are granted, counted, and applied is discipline — and it has been reformed drastically, including the abolition of the medieval reckoning in days and years.
Disciplines are the fourth of four levels. Above them stand dogmas, which can never change; doctrines, owed religious submission of intellect and will; and devotions, which were never required at all.
