Romano Pontifici Eligendo was the Apostolic Constitution governing the election of popes that was promulgated by Pope Paul VI in 1975. It instituted a number of far-reaching reforms in the process of electing popes. An Apostolic Constitution is a highest category of a document of instruction issued by the Roman Catholic Pope or by a Church council with the approval of the Pope. ... His Holiness Pope Paul VI, born Giovanni Battista Enrico Antonio Maria Montini (September 26, 1897 – August 6, 1978), reigned as Pope and as sovereign of the Vatican City from 1963 to 1978. ... 1975 was a common year starting on Wednesday (the link is to a full 1975 calendar). ...

Ban on cardinals over eighty voting

Its most dramatic reform was to give formal structure to Paul's already announced decision to prohibit cardinals over the age of eighty from participating and voting in the election of popes.

Restrictions on conduct of the conclave

It also imposed extremely strict regulations on the conduct of papal conclaves, including the requirement that the windows of the Sistine chapel be boarded up during a conclave. Many cardinals complained that the restrictions were excessive during the two conclaves of 1978 and they were subsequently abolished by Pope John Paul II in his 1996 Apostolic Constitution Universi Dominici Gregis. The Sistine Chapel is the location of the conclave. ... The Sistine Chapel (Italian: Cappella Sistina) is a chapel in the Palace of the Vatican, the official residence of the Roman Catholic Pope in the Vatican City. ... His Holiness Pope John Paul II (Latin: ), born Karol Józef Wojtyła [1] (May 18, 1920 – April 2, 2005), reigned as Pope of the Roman Catholic Church and sovereign of Vatican City for almost 27 years, from 16 October 1978 until his death. ... Universi Dominici Gregis is an apostolic constitution of the Roman Catholic Church issued by Pope John Paul II in 1996. ...

Requirement that successor be crowned

One other notable feature was that, while Pope Paul himself had abandoned the wearing of his Papal Tiara, he explicitly required that his successor must be crowned in a Papal Coronation.^{[1] (http://en.wikipedia.org/wiki/Romano_Pontifici_Eligendo#endnote_paul6constitution)} However Popes John Paul I and John Paul II opted not to obey this rule, with the latter in his homily at his Papal Inauguration suggesting erroniously that Paul's constitution had left it free for future popes to decide whether or not to be crowned.^{[2] (http://en.wikipedia.org/wiki/Romano_Pontifici_Eligendo#endnote_homily2)} 1834 Tiara of Pope Gregory XVI The Papal Tiara, also known as the Triple Tiara, in Latin as the Triregnum, or in Italian as the Triregno,[1] is the three-tiered jewelled papal crown of Byzantine and Persian origin that is the symbol of the papacy. ... Pope Pius XII, in coronation robes and wearing the 1877 Papal Tiara, is carried through St. ... His Holiness Pope John Paul I (in Latin ), born Albino Luciani (October 17, 1912 – September 28, 1978), reigned as pope and as sovereign of the Vatican City from August 26, 1978 to September 28, 1978. ... His Holiness Pope John Paul II (Latin: ), born Karol Józef Wojtyła [1] (May 18, 1920 – April 2, 2005), reigned as Pope of the Roman Catholic Church and sovereign of Vatican City for almost 27 years, from 16 October 1978 until his death. ... Pope John Paul I at the first papal inauguration, in September 1978. ...

John Paul ultimately changed this requirement in his own 1996 Apostolic Constitution, leaving it free to each successor to decide on their method of inauguration. An inauguration is a ceremony of formal investiture whereby an individual assumes an office or position of authority. ...

Footnotes

1. ^  Romano Pontifici Eligendo (1975), No. 92.

1. ^  Papal Inauguration Homily of Pope John Paul II, L'Osservatore Romano (Text of the Homily) (http://www.catholicculture.org/docs/doc_view.cfm?recnum=1138)