The Pontifex Maximus was the high priest of the Ancient Roman College of Pontiffs. This was the most important position in the Ancient Roman religion, open only to patricians until 254 BC, when a plebeian first occupied this post. A distinctly religious office under the early Roman Republic, it gradually became politicized until, beginning with Augustus, it was subsumed into the Imperial office. Its last use with reference to the emperors is in inscriptions of Gratian, Emperor from 375 to 383, who, however, then decided to omit the words "pontifex maximus" from his title.
It is often said that Pope Damasus I, Bishop of Rome from 366 to 384 and so for the whole of the reign of Gratian, was the first pope to use the title "Pontifex Maximus", but no document is cited in support of this statement. Emperor Theodosius I's edict De fide catholica of 27 February 380 refers to Damasus as a "pontifex", not as the "Pontifex Maximus". It is at a much later stage in history that the title "Pontifex Maximus" appears on buildings, monuments and coins of a specific pope of Renaissance and modern times.
An alternative view is that pontifex means "preparer of the road", derived from the Etruscan word pont, meaning "road". A minority opinion is that the word is a corruption of a similar-sounding but etymologically unrelated Etruscan word for priest.
The official residence of the Pontifex Maximus was the Domus Publica which stood between the House of the Vestal Virgins and the Via Sacra, close to the Regia, in the Roman Forum. His religious duties were carried out from the Regia or 'house of the king'.
Unless the pontifex maximus was also a magistrate at the same time, he was not allowed to wear the toga praetexta, i.e. toga with the purple border. However, he could be recognized by the iron knife (secespita) or the patera and the distinctive robes or toga with part of the mantle covering the head.
The Pontifex was not simply a priest. He had both political and religious authority. It is not clear which of the two came first or had the most importance. In practice, particularly during the late Republic, the office of Pontifex Maximus was generally held by a member of a politically prominent family. It was a coveted position mainly for the great prestige it confers on the holder; Julius Caesar became pontifex in 73 BC and pontifex maximus in 63 BC. Being Pontifex Maximus was not a full-time job and did not preclude the office-holder from holding a secular magistracy or serving in the military.
The most recent general study of the pontifical college (Van Haeperen 2002), omits the earliest periods of Roman history, as too little is known. The major Roman source, Varro's book on the pontiffs, is lost: only a little of it survives in Aulus Gellius and Nonius Marcellus. More information is to be found in remarks by Cicero, Livy, Dionysius of Halicarnassus, Valerius Maximus, in Plutarch's vita of Numa Pompilius, Festus' summaries of Verrius Flaccus, and in later writers. Some of these sources present an extensive list of everyday actions that were taboo for the Pontifex Maximus; it seems difficult to reconcile these lists with evidence that many Pontifices Maximi were prominent members of society who lived normal, non-restricted lives.
According to Livy in his "History of Rome", an ancient instruction written in archaic letters commands: "Let him who is the Praetor Maximus fasten a nail on the Ides of September." This notice was fastened up on the right side of the Temple of Jupiter Optimus Maximus, next to the chapel of Minerva. This nail is said to have marked the number of the year. It was in accordance with this direction that the consul Horatius dedicated the Temple of Jupiter Optimus Maximus in the year following the expulsion of the kings; from the Consuls the ceremony of fastening the nails passed to the Dictators, because they possessed greater authority. As the custom had been subsequently dropped, it was felt to be of sufficient importance to require the appointment of a Dictator. L. Manlius was accordingly nominated but his appointment was due to political rather than religious reasons. He was eager to command in the war with the Hernici. He caused a very angry feeling among the men liable to serve by the inconsiderate way in which he conducted the enrolment. At last, in consequence of the unanimous resistance offered by the tribunes of the plebs, he gave way, either voluntarily or through compulsion, and laid down his Dictatorship. Since then, this rite has been performed by the Rex Sacrorum.
The main duty of the Pontifices was to maintain 'pax deorum' or 'peace of the gods'.
The immense authority of the sacred college of pontiffs was centered on the Pontifex Maximus, the other pontifices forming his consilium or advising body. His functions were partly sacrificial or ritualistic, but these were the least important. His real power lay in the administration of jus divinum or divine law; the information collected by the pontifices related to the Roman religious tradition was bound in a corpus which summarized dogma and other concepts. The chief departments of jus divinum may be described as follows:
The pontifices had many relevant and prestigious functions such as being in charge of caring for the state archives, the keeping the official minutes of elected magistrates (see Fasti) and list of magistrates, and they kept the records of their own decisions (commentarii) and of the chief events of each year, the so-called "public diaries", the Annales maximi.
The pontifex maximus is also subject to several taboos. Among them is the prohibition from leaving Italy. However, Plutarch described Publius Cornelius Scipio Nasica Serapio (141 - 132 BC) as the first to leave Italy and thus break the sacred taboo after being forced by the Senate to leave Italy. Publius Licinius Crassus Dives Mucianus (132 - 130 BC) was the first to leave Italy voluntarily. Afterwards it became common and no longer against the law for the pontifex maximus to leave Italy. Among the most notable of which was Julius Caesar (63 - 44 BC).
The Pontifices were in charge of the Roman calendar and determined when intercalary days needed to be added to sync the calendar to the seasons. Since the Pontifices were often politicians, and because a Roman magistrate's term of office corresponded with a calendar year, this power was prone to abuse: a Pontifex could lengthen a year in which he or one of his political allies was in office, or refuse to lengthen one in which his opponents were in power. Under his authority as Pontifex Maximus, Julius Caesar introduced the calendar reform that created the Julian calendar, with a fault under a day per century, easily corrected by a modification of the rules for bisextile days (only added in a leap-year) to produce our present Gregorian calendar.
From this point on, Pontifex Maximus was one of the many titles of the Emperor, slowly losing its specific and historical powers and becoming simply a referent for the sacral aspect of imperial duties and powers. During the Imperial period, a promagister (vice-master) performed the duties of the pontifex maximus in lieu of the emperors whenever they were absent (Van Haeperen). In post-Severan times (post AD 235), the small number of pagan senators interested in becoming pontiffs led to a change in the pattern of office holding. In Republican and Imperial times no more than one family member of a gens was member of the College of Pontiffs, nor did one person hold more than one priesthood in this collegium. Obviously these rules where loosened in the later part of the third century AD. In periods of joint rule, two pontifices maximi could serve together, as Pupienus and Balbinus did in 238 — a situation unthinkable in Republican times. In the crisis of the Third Century, usurpers did not hesitate to claim for themselves the role not only of Emperor but of Pontifex Maximus as well. Even the early Christian Emperors continued to use it; it was only relinquished by Gratian, possibly in AD 376 at the time of his visit to Rome , or more probably in 383 when a delegation of pagan senators implored him to restore the Altar of Victory in the Senate House.
It is not clear if the word Pontifex was commonly used by early 3rd-century Christianity, as it was later, to denote a bishop. Tertullian's usage is unusual in that most of the technical terms of Roman paganism were avoided in the vocabulary of Christian Latin in favour of neologisms or Greek words.
The last traces of emperors being at the same time chief pontiffs are found in inscriptions of Valentinian, Valens, and Gratianus (Orelli, Inscript. n1117, 1118). From the time of Theodosius I (379–395), the emperors no longer appear in the dignity of pontiff; but the title was later applied to the Christian bishop of Rome. In 382, the Emperor Gratian, at the urging of St. Ambrose, removed the Altar of Victory from the Forum, withdrew the state subsidies that funded many pagan activities and formally renounced the title of Pontifex Maximus. It is said that Pope Damasus I was the first Bishop of Rome to assume the title, Other sources say that the use of such titles by bishops, including the Bishop of Rome, came later. The title pontifex continued to be a title for both the bishop of Rome and other bishops. In Emperor Theodosius's edict De fide catholica of 27 February 380, enacted in Thessalonica and published in Constantinople for the whole empire, by which he established Catholic Christianity as the official religion of the empire, he referred to Damasus as a pontifex,while calling Peter an episcopus : "... the profession of that religion which was delivered to the Romans by the divine Apostle Peter, as it has been preserved by faithful tradition and which is now professed by the Pontiff Damasus and by Peter, Bishop of Alexandria ... We authorize the followers of this law to assume the title Catholic Christians ..." Some see in this an implied significant differentiation, but the title pontifex maximus is not used in the text; pontifex is used instead: "... quamque pontificem damasum sequi claret et petrum alexandriae episcopum..." (Theodosian Code XVI.1.2; and Sozomen, "Ecclesiastical History", VII, iv. ).
Without quoting its source, the Encyclopædia Britannica attributes to Pope Leo I (440-461) the assumption of the title Pontifex Maximus. This was a time when the declining Roman Empire was in transition from pagan to Christian, and Constantinople would begin to assert itself to pre-eminence, historically leading to conflict with the Bishops of Rome. Soon there would be the final collapse of the Roman Empire with the invasions of the Huns and the Vandals. Others say, again without quoting documentary evidence, that it was more than a century later when for the first time a Pope (Gregory I) employed "Pontifex Maximus"
While the title Pontifex Maximus has for some centuries been used in inscriptions referring to the Popes, it has never been included in the official list of papal titles published in the Annuario Pontificio, which instead includes "Supreme Pontiff of the whole Church" (in Latin, Summus Pontifex Ecclesiae Universalis) as the fourth official title, the first being "Bishop of Rome".
The terms pontifex maximus and summus pontifex were for centuries used not only of the Bishop of Rome but of other bishops also. Hilary of Arles (d. 449) is styled "summus pontifex" by Eucherius of Lyons (P. L., L, 773), and Lanfranc is termed "primas et pontifex summus" by his biographer, Milo Crispin (P. L., CL, 10); they were doubtless originally employed with reference to the Jewish high-priest, whose place the Christian bishops were regarded as holding each in his own diocese (I Clement 40), but from the eleventh century they appear to be applied only to the Pope.
The Oxford Dictionary of the Christian Church says that it was in the fifteenth century that "Pontifex Maximus" became a regular title of honour for Popes.
After Christ himself, the pope is the "high priest" (the veritable meaning of summus pontifex and "pontifex maximus") of the Catholic religion.
The title of "Pontifex Maximus", which is now applied to the pope, though not included in his official list of titles, has a very ancient history, dating back to the times of the Roman Republic. The only title applied to the Pope that has a longer documented history is the word "pope" itself (in Greek, "πάππας"), which is found already in the time of Homer. This title likewise is not included in the official list of his titles, but is used in official documents (such as the headings of encyclicals and similar documents) far more commonly than the title "Pontifex Maximus", which is in practice used in little more than inscriptions of buildings.
Eastern traditions, from the ancient Egyptian to the Japanese, carried the concept even further, according their sovereigns demigod status.
With the adoption of Christianity, the Roman emperors took it on themselves to issue decrees on matters regarding the Christian Church. Unlike the Pontifex Maximus, they did not themselves function as priests, but they acted practically as head of the official religion, a tradition that continued with the Byzantine emperors. In line with the theory of Moscow as the Third Rome, the Russian Tsars exercised supreme authority over the Russian Orthodox Church.
With the English Reformation, the sovereign of England became Supreme Governor of the Church of England and insisted on being recognised as such. Only at a later stage was effective separation of church and state introduced. Much the same occurred in other countries affected by the Protestant Reformation.
Even in countries where there was no formal break with the Holy See, various sovereigns assumed similar authority. An example is Joseph II, Holy Roman Emperor, whose ecclesiastical policy is described in the Catholic Encyclopedia article on him.
A secular equivalent of the ruler as head of religion is that of the philosopher king, based on a notion in Plato's Republic. Several rulers have been pictured as, at least to some extent, embodying that concept. Some of them are listed in Philosopher king#Historical philosopher-kings.
From some indeterminate later date to present, the title "Pontifex Maximus" is applied to the Popes.
The White separatist group the (former) World Church of the Creator referred to the founder of Creativity, Ben Klassen, and leader Matt Hale as Pontifex Maximus. Hale was also commonly referred to as "the Great Promoter" by church membership, a symbolic rather than literal English translation of Pontifex Maximus.