The papal inauguration celebration, with or without a coronation, has only symbolic significance, as a pope assumes office immediately on giving his consent to a valid election.
[4] If the new pope is already a bishop, as is normally the case, his election is announced immediately to the people gathered in Saint Peter's Square and he gives them his blessing.
When Gregory XI did return to Rome, the Lateran Palace was badly in need of repair, so the popes made the Vatican their residence and transferred coronations to Saint Peter's Basilica.
Following this, at least from the beginning of the 16th century, the newly elected pope was carried in state through St. Peter's Basilica on the sedia gestatoria under a white canopy, with the papal flabella (ceremonial fans) to either side.
Three times, the procession was stopped, and a bundle of flax lashed to a gilded staff was burnt before the newly elected pontiff, while a master of ceremonies said: Pater Sancte, sic transit gloria mundi (Holy Father, thus passes the glory of the world) as a symbolic reminder to set aside materialism and vanity.
After the Confiteor, the pope was seated on the sedia gestatoria, which was resting on the ground, and the three senior cardinal bishops approached him wearing mitres.
[10][11]In the 11th and 12th centuries, the immantatio, or bestowal of the mantum (a papal vestment consisting of a very long red cope fastened with an elaborate morse) on the newly elected pope was regarded as especially symbolic of investiture with papal authority, and was conferred with the words: "I invest thee with the Roman papacy, that thou rule over the city and the world.
After the Dean of the College of Cardinals recited a few prayers, including the Lord's Prayer and a collect, the senior cardinal deacon, the protodeacon, removed the pope's mitre and placed the tiara on his head with the words: Accipe tiaram tribus coronis ornatam, et scias te esse patrem principum et regum, rectorem orbis in terra vicarium Salvatoris nostri Jesu Christi, cui est honor et gloria in saecula saeculorum.Receive the tiara adorned with three crowns, and know that you are the father of princes and kings, the ruler of the world, the vicar of our Savior Jesus Christ on earth, to whom be all honor and glory, world without end.
The last act of the inauguration of a new pope is still the formal taking possession (possessio) of his cathedra as Bishop of Rome in the Archbasilica of St. John Lateran.
He receives the kiss of peace and listens to the reading of a passage of Holy Scripture, whereupon he pronounces an address that used to be called the sermo inthronisticus.
In ancient times, the letters that the pope sent to the patriarchs in token of being in communion with them in the same faith were called litterae inthronisticae or syllabai enthronistikai.
Leo XIII was crowned in the Sistine Chapel,[27] due to fears that anti-clerical mobs, inspired by Italian unification, might attack the Basilica and disrupt the ceremony.
[28] The ceremony, which lasted for six hours, was attended by leading dignitaries; these included the heir to the Italian throne, the Prince of Piedmont, former kings Ferdinand I of Bulgaria and Alfonso XIII of Spain, the 16th Duke of Norfolk (representing King George VI of the United Kingdom), and the Irish Taoiseach, Éamon de Valera, the last two being in evening dress (white tie and tails).
[29] His successor, Pope John Paul I, opted not to be crowned and to have instead a less elaborate "solemn Mass to mark the start of his ministry as Supreme Pastor" in September 1978.