Second Council of Nicaea · Worship
The decree of October 13, 787, ordered that images of Christ, Mary, the angels, and the saints be set up in churches and honored with kisses, incense, and lights.

First Lateran Council · Discipline
Forbade priests, deacons, and subdeacons to live with wives, condemned simony, and granted the crusading indulgence.

Second Lateran Council · Discipline
Declared marriages contracted by clergy in major orders to be no marriages at all, making clerical celibacy the law of the Western church.

Ad abolendam (Lucius III, Council of Verona) · Persecution
Issued November 4, 1184, it required bishops to search out heretics and hand the unrepentant to the secular power for punishment: the beginning of the Inquisition.

Fourth Lateran Council · Sacraments
Defined transubstantiation (constitution 1), bound every Christian to confess to a priest at least once a year (constitution 21), and ordered rulers to expel heretics from their lands (constitution 3).

Council of Toulouse · Scripture
Forbade the laity to possess the books of the Old or New Testament, allowing only the Psalter or a breviary, and “most strictly” forbade any translation of them.

Ad extirpanda (Innocent IV) · Persecution
Issued May 15, 1252, it authorized the use of torture to extract confessions from suspected heretics.

Unam sanctam (Boniface VIII) · Papacy
Issued November 18, 1302, it declared that it is “altogether necessary to salvation for every human creature to be subject to the Roman pontiff.”

Unigenitus Dei Filius (Clement VI) · Salvation
Issued January 27, 1343, it set out the doctrine of the treasury of merit, from which the Church grants indulgences.

The Constitutions of Oxford (Archbishop Arundel) · Scripture
Forbade anyone to translate Scripture into English, or to read such a translation, without the approval of the bishop, aimed at the Lollards and the Wycliffe Bible.

Council of Constance · Sacraments & Persecution
Condemned Wycliffe’s teaching on May 4, withheld the cup from the laity on June 15, and condemned Jan Hus, who was burned on July 6, 1415.

Council of Florence · Salvation & Sacraments
Laetentur caeli (July 6, 1439) defined purgatory and the primacy of the Roman pontiff over the whole Church; the Decree for the Armenians (November 22, 1439) defined the seven sacraments.

Cantate Domino (Council of Florence) · Scripture & Salvation
Issued February 4, 1442, it listed the canon including the Apocrypha and declared that none outside the Catholic Church can be saved.

Salvator noster (Sixtus IV) · Salvation
Issued August 3, 1476, it extended indulgences to the souls in purgatory, the claim on which Tetzel’s preaching rested.

Fifth Lateran Council · Scripture & Papacy
Inter sollicitudines (May 4, 1515) forbade printing any book without prior church approval.

Pastor aeternus (December 19, 1516) declared the pope’s authority over councils.

Exsurge Domine (Leo X) · Salvation & Persecution
Issued June 15, 1520, it condemned forty-one propositions of Luther, among them: “That heretics should be burned is contrary to the will of the Spirit,” and “Purgatory cannot be proved from Holy Scripture” (propositions 33 and 37).

Decet Romanum Pontificem (Leo X) · Papacy
Issued January 3, 1521, it excommunicated Martin Luther.

Council of Trent, Session 4 · Scripture
On April 8, 1546, the council received “with equal affection of piety, and reverence” the books of Scripture and unwritten traditions, fixed the canon to include the Apocrypha under anathema, and declared the Latin Vulgate the authentic text.

Council of Trent, Session 6 · Salvation
On January 13, 1547, the council defined justification as the renewal of the inner man and condemned justification by faith alone in thirty-three canons.

Council of Trent, Session 7 · Sacraments
On March 3, 1547, the council anathematized those who deny that there are seven sacraments, or that they confer grace by the act performed (ex opere operato).

Council of Trent, Sessions 13 and 14 · Sacraments
Session 13 (October 11, 1551) defined transubstantiation and required that the host be adored; Session 14 (November 25, 1551) required the confession to a priest of every mortal sin and its circumstances.

Council of Trent, Session 22 · Sacraments
On September 17, 1562, the council taught that the sacrifice of the Mass “is truly propitiatory” and is offered “as well for the living as the dead.”

Council of Trent, Session 25 · Worship
On December 3–4, 1563, the council decreed on purgatory, the invocation and veneration of the saints, relics, images, and indulgences.

Dominici gregis custodiae (Pius IV) · Scripture
Issued March 24, 1564, it published the Index of Prohibited Books. Its fourth rule permitted vernacular Bibles only by license of a bishop or inquisitor, and denied absolution to anyone who read one without it.

Iniunctum nobis (Pius IV) · Papacy
Issued November 13, 1564, it imposed the Profession of the Tridentine Faith on all clergy and teachers, binding them to Trent’s decrees and to obedience to the Roman pontiff.

Regnans in excelsis (Pius V) · Papacy
Issued February 25, 1570, it excommunicated Elizabeth I and released her subjects from their allegiance.

Unigenitus (Clement XI) · Scripture
Issued September 8, 1713, it condemned the propositions of Pasquier Quesnel, including “The reading of sacred Scripture is for all.”

Ineffabilis Deus (Pius IX) · Mary
Issued December 8, 1854, it defined the Immaculate Conception of Mary.

Quanta cura and the Syllabus of Errors (Pius IX) · Papacy & Liberty
Issued December 8, 1864, it condemned liberty of conscience and worship, and numbered Bible societies among the “pests” of the age.

Pastor aeternus (First Vatican Council) · Papacy
Issued July 18, 1870, it defined the universal jurisdiction and the infallibility of the Roman pontiff, under anathema.

Apostolicae curae (Leo XIII) · Papacy
Declared Anglican orders, conferred by the ordinal of the English Reformation, “absolutely null and utterly void.”

Munificentissimus Deus (Pius XII) · Mary
Issued November 1, 1950, it defined the bodily Assumption of Mary into heaven.

Dei Verbum (Second Vatican Council) · Scripture
Issued November 18, 1965, it restated that Tradition and Scripture are to be received with equal reverence, and that their authentic interpretation belongs to the Magisterium alone.