A function of the college is to advise the pope about church matters when he summons them to an ordinary consistory, a term derived from the Roman Emperor's crown council. It also attends various functions as a matter of protocol, for example, during the canonization process.
It also convenes on the death or resignation of a pope as a papal conclave to elect a successor, but is then restricted to eligible Cardinals under the age limit, which was set for the first time in 1970 by Pope Paul VI at 80.
Historically, cardinals were the clergy serving parishes of the city of Rome under its bishop, the pope. The College acquired particular importance following the crowning of Henry IV as King of Germany and Holy Roman Emperor at the age of six, after the unexpected death of Henry III in 1056. Until then, the Holy See was often bitterly fought for among Rome's aristocratic families and external secular authorities had significant influence over who was to be appointed pope, and the Holy Roman Emperor in particular had the special power to appoint him. This was significant as the aims and views of the Holy Roman Emperor and the Church did not always coincide. Churchmen involved in what has become known as the Gregorian Reform took advantage of the new king's lack of power and in 1059 reserved the election of the pope to the clergy of the Church in Rome. This was part of a larger power struggle, which became known as the Investiture Controversy, as the Church and the Emperor each attempted to gain more control over the appointment of bishops, and in doing so wield more influence in the lands and governments they were appointed to. Reserving to the cardinals the election of the pope represented a significant shift in the balance of power in the Early Medieval world. From the beginning of the 12th century, the College of Cardinals started to meet as such, when the cardinal bishops, cardinal priests and cardinal deacons ceased acting as separate groups.
The word cardinal is derived from the Latin cardo, meaning "hinge." The office of cardinal as it is known today slowly evolved during the first millennium from the clergy of Rome. "The first time that the term cardinal appears in the Liber Pontificalis is in the biography of Pope Stephen III(IV) when in the Roman Synod of 769, it was decided that the Roman pontiff should be elected from among the deacons and cardinal priests."
In 845 the Council of Meaux "required Bishops to establish Cardinal titles or parishes in their towns and outlining districts." At the same time, the popes began referring to the cardinal priests of Rome to serves as legates and delegates within Rome at ceremonies, synods, councils, etc., as well as abroad on diplomatic missions and councils. Those who were assigned to the latter roles were given the titles of Legatus a latere (Cardinal Legate) and Missus Specialis (Special Missions).
During the pontificate of Stephen V (816-17), the three classes of the College that are present today began to form. Stephen decreed that all cardinal-bishops were bound to sing Mass on rotation at the high altar at St. Peter's Basilica, one per Sunday. The first class to form was that of the cardinal-deacons, direct theological descendants of the original seven ordained in Acts 6, followed by the cardinal-priests, and finally, the cardinal-bishops.
The College played an integral part in various reforms within the Church as well, as early as the pontificate of Pope Leo IX (1050). In the 12th century, the Third Lateran Council declared that only Cardinals could assume the papacy, a requirement that has since lapsed. In 1130, under Urban II, all the classes were permitted to take part in papal elections; up to this point, only cardinal-bishops had this role.
By the end of the 14th century, the practice of solely Italian cardinals had ceased. Between the 14th century and 17th century, there was much struggle for the College between the cardinals of the day and the reigning popes. The most effective way for a pope to increase his power was to increase the number of cardinals, promoting those who had nominated him. Those cardinals in power saw these actions as an attempt to weaken their influence. In 1517, Pope Leo X added another thirty-one cardinals, bringing the total to sixty-five so that he could have a supportive majority among the College of Cardinals. Paul IV brought the total to seventy. Pope Pius IV raised an additional six. By the papacy of Sixtus V (1585–1590), the number was set at seventy, divided among fourteen cardinal-deacons, fifty cardinal-priests, and six cardinal-bishops.
Under the terms of Pope Paul VI's motu proprioIngravescentem Aetatem, cardinals who reached the age of 80 before a conclave opened had no vote in papal elections. Pope John Paul II's Universi Dominici gregis of 22 February 1996 modified that slightly, so that cardinals who have reached the age of 80 before the day the see becomes vacant do not have a vote.
Canon law sets the general qualifications required of someone to be appointed bishop quite broadly, requiring someone of faith and good reputation, thirty-five years old, with a certain level of education. The cardinals have nevertheless elected the Bishop of Rome from among their own membership since the election of Pope Urban VI in 1378. The conclave rules specify the procedures to be followed should they elect someone residing outside Vatican City or not yet a bishop.
As of 23 March 2017[update], there are a total of 223 cardinals, of whom 118 are under 80. The Holy See announced on 20 March 2015 that Pope Francis had accepted the resignation by Cardinal Keith O'Brien of the rights and privileges of a Cardinal, although he retains the title. As a result, 117 cardinals are eligible to participate in a future papal election. Of those 117, 19 were appointed by Pope John Paul II, 54 by Pope Benedict XVI, and 44 by Pope Francis.
Lluís Martínez Sistach is the next cardinal to turn 80 on 29 April 2017, when he will lose his right to participate in a conclave.
The following is the list of all cardinals living as of 23 March 2017[update]. Cardinals appear in order of precedence, based on seniority by date of appointment. Michael Michai Kitbunchu is the most senior member of the College by length of service (the Protopriest). Angelo Sodano has the highest precedence as a Cardinal Bishop and Dean of the College of Cardinals. Roger Etchegaray has second highest precedence as a fellow Cardinal Bishop and Sub-Dean of the College of Cardinals. The oldest living cardinal is José de Jesús Pimiento Rodríguez, born in 1919.
Within the College of Cardinals, there are three categories, the highest-ranked Cardinal Bishops, then Cardinal Priests, and finally Cardinal Deacons. Within each category, cardinals are ranked by seniority of appointment to that category. Despite these titles, almost every cardinal is, since the pontificate of Pope John XXIII (1958–1963), a bishop. Any one not a bishop when his appointment is announced has generally been consecrated bishop before his formal installation, although a few priests appointed cardinals when near or over 80 have obtained permission not to become bishops.
Most of the cardinals are from the Latin Church; those who are from the Eastern Catholic Churches have their church indicated. Cardinals who are not electors have their date of birth and age highlighted in red.
As of 23 March 2017[update], the College had 223 members, 117 of whom were eligible to participate in a conclave. The group's size has historically been limited by popes, ecumenical councils, and even the College itself. From 1099 to 1986, the total number of cardinals appointed was approximately 2,900 (excluding possibly undocumented 12th-century cardinals, cardinals appointed during the Western Schism by pontiffs now considered to be antipopes, and subject to some other sources of uncertainty), nearly half of whom were created after 1655.
^In 2003 Pope John Paul II announced he was also creating one cardinal secretly (in pectore). This appointment would have taken effect if it had been announced before the Pope's death. There was press speculation that it was Tadeusz Kondrusiewicz, Archbishop of Moscow, Joseph Zen Ze-kiun, Bishop of Hong Kong, or Archbishop Stanislaw Dziwisz, the pope's private secretary. Zen said he thought a mainland Chinese prelate was more likely than he. On 6 April 2005 a Vatican spokesman said that Pope John Paul II had not announced the name of this cardinal before witnesses prior to his death and that the appointment was therefore without effect.
^Cardinal Njue's date of birth is unknown. The Vatican provides only the year 1944.
^Cardinal-Deacons have the right to apply to become Cardinal-Priests after ten years as a Cardinal-Deacon. All living eligible Cardinal-Deacons have exercised this right, with the sole exception of Renato Raffaele Martino.