Tiara, the papal crown, a costly covering for the head, ornamented with precious stones and pearls, which is shaped like a bee-hive, has a small cross at its highest point, and is also equipped with three royal diadems. On account of the three diadems it is sometimes called triregnum. The tiara is a non-liturgical ornament, which, therefore, is only worn for non-liturgical ceremonies, ceremonial procession to church and back, ceremonial papal processions, such as took place upon stated occasions until Rome was occupied by the Piedmontese, and at solemn acts of jurisdiction, as, for example, solemn dogmatic decisions. The pope, like the bishops, wears a mitre at pontifical liturgical functions. The tiara is first mentioned in the “Vita” of Pope Constantine (708-715) contained in the “Liber Pontificalis“. It is here called camelaucum; it is then mentioned in what is called the “Constitutum Constantini”, the supposed donation of the Emperor Constantine, probably forged in the eighth century. Among the prerogatives assigned to the pope in this document there is especially a white ornament for the head called phrygium, which distinguished him; this naturally presupposes that, at the era the document was written, it was customary for the pope to wear such a head covering. Three periods may be distinguished in the development of the tiara. The first period extends to the time when it was adorned with a royal circlet or diadem; in this period the papal ornament for the head was, as is clear from the “Constitutum Constantini” and from the ninth Ordo of Mabillon (ninth century), merely a helmet-like cap of white material. There may have been a trimming around the lower rim of the cap, but this had still in no way the character of a royal circlet. It is not positively known at what date the papal head covering was adorned with such a circlet. At the time the Donation of Constantine appeared, that is in the eighth century, the papal head covering had still no royal circlet, as is evident from the text of the document. In the ninth century also such circlet does not seem to have existed. It is true that the Ninth Ordo calls the papal cap regnum, but in the description that the Ordo gives of this cap we hear nothing at all of a crown, but merely that the regnum was a helmet-like cap made of white material. The monumental remains give no clue as to theperiod at which the papal head covering became ornamented with a royal circlet. Up into the twelfth century the tiara was not only seldom represented in art, but it is also uncertainwhether the ornamental strip on the lower edge is intended to represent merely a trimming or a diadem. This is especially true of the representations of the tiara on the coins of Sergius III (904-911) and Benedict VII (974-983), the only representations of the tenth century and also the earliest ones. Probably the papal head covering received the circlet atthe time when the mitre developed from the tiara, perhaps in the tenth century, in order to distinguish the mitre and tiara from each other. In any case the latter was provided with a circlet by about 1130, as is learned from a statement of Suger of St. Denis. The first proven appearance of the word tiara as the designation of the papal head covering is in the life of Paschal II (1099-1118), in the “Liber Pontificalis“.
The second period of the development of the tiara extends to the pontificate of Boniface VIII (1294-1303). There are a large number of representations of the tiara belonging to this period, and of these the Roman ones have naturally the most value. The diadem remained a simple although richly-ornamented ring up into the second half of the thirteenth century; it then became an antique or tooth-edged crown. The two lappets (caudae) at the back of the tiara are first seen in the pictures and sculpture in the thirteenthcentury, but were undoubtedly customary before this. Strange to say they were black in color, as is evident both from the monumental remains and from the inventories, and this color was retained even into the fifteenth century. When the tiara is represented in sculpture and painting as a piece of braiding, this seems to arise from the fact that in the thirteenth century the tiara was made of strips braided together.
Of much importance for the tiara was the third period of development that began with the pontificate of Boniface VIII. It is evident from the inventory of the papal treasures of 1295 that the tiara at that era had still only one royal circlet. A change, however, was soon to appear. During the pontificate of Boniface VIII a second crown was added to the former one. Three statues of the pope which were made during his lifetime and under his eyes, and of which two were ordered by Boniface himself, leave no doubt as to this. Two of these statues are in the crypt of St. Peter’s, and the third, generally called erroneously a statue of Nicholas IV, is in the Church of the Lateran. In all three the tiara has two crowns. What led Boniface VIII to make this change, whether merely love of pomp, or whether he desired to express by the tiara with two crowns his opinions concerning the double papal authority, cannot be determined. The first notice of three crowns is contained in an inventory of the papal treasure of the year 1315 or 1316. As to the tombs of the popes, the monument of Benedict XI (d. 1304) at Perugia shows a tiara of the early kind; the grave and statue of Clement V at Uzeste in the Gironde were mutilated by the Calvinists, so that nothing can be learned from them regarding the form of the tiara. The statue upon the tomb of John XXII is adorned with a tiara having two crowns. The earliest representation of a tiara with three crowns, therefore, is offered by the effigy of Benedict XII (d. 1342), the remains of which are preserved in the museum at Avignon. The tiara with three crowns is, consequently, the rule upon the monuments from the second half of the fourteenth century, even though, as an anachronism, there are isolated instances of the tiara with one crown up into the fifteenth century. Since the fifteenth century the tiara has received no changes worthy of note. Costly tiaras were made especially in the pontificates of Paul II (d. 1464), Sixtus IV (d. 1484), and above all in the pontificate of Julius II, who had a tiara valued at 200,000 ducats, made by the jeweller Caradosso of Milan.
Various hypotheses, some very singular, have been proposed as to the origin of the papal head covering, the discussion of which here is unnecessary. The earliest name of the papal cap, camelaucum, as well as the Donation of Constantine, clearly point to the Byzantine East; it is hardly to be doubted that the model from which the papal cap was taken is to be found in the camelaucum of the Byzantine court dress. The adoption by the popes of the camelaucum as an ornament for the head in the seventh or at the latest in the eighth century is sufficiently explained by the important position which they had attained just at this period in Italy and chiefly at Rome; though they could not assume a crown, as they were not sovereign, they could wear a camelaucum, which was worn by the dignitaries of the Byzantine Empire.