Regnum a name for the tiara or diadem of the popes, encircled with three crowns. It is (says Innocent III. cir. 1200) the imperial crown, representing the pope's power as plenary and absolute over all the faithful. According to some authors, Hormisdas first wore a crown which had been sent to him as a mark of fealty by the emperor Anastasius, to whom Clovis had presented it in 550, while some refer it to a gift of Constantine to pope Sylvester. At the entrance of a church the pope, when borne on his litter, laid aside the regnum and put on a precious mitre, but resumed the former when he left the building. Paul II made a new regnum, and enriched it with precious stones, when its use had long lain dormant. At first it was a tall round or conical cap, ending in a round ball, and wreathed with a single gold crown, representing regal and temporal power. It is mentioned in the 11th century. In the 9th century, on mosaics, Nicholas I is represented wearing two circles, the lower labelled "The crown of the kingdom, from God's hand," and the upper inscribed "The crown of empire, from St. Peter's hand." Boniface VIII (1294-1303) added a second or spiritual crown, while Benedict XII (1334), others say John XII or Urban V, contributed the third coronet of sacerdotal sovereignty, and about that time the ornament assumed an oval form, and was no longer straight-sided. The patriarch of Constantinople wears two crowns on the tiara. On putting on the tiara, the cardinal-deacon says to the pope, "Receive the tiara, adorned with three crowns, and know that thou art father of kings and princes, the ruler of the world." The crowns represent the three realms of heaven, earth, and purgatory, according to Baur; but as Jewel explains it, the three divisions of the earth — Europe, Asia, and Africa. Pope Adrian VI's effigy at Viterbo has no crowns on the tiara. SEE TIARA.