Urbi et Orbi

Urbi et Orbi (lit. 'to the city [of Rome] and to the world') denotes a papal address and apostolic blessing given by the pope on certain solemn occasions.
The term Urbi et Orbi evolved from the consciousness of the ancient Roman Empire. The invocation is expressed by the pope in his capacity as both the bishop of Rome (urbs = city; urbi the corresponding dative form; compare: urban) and the head of the Roman Catholic Church throughout the world (orbis = earth; orbi the corresponding dative form; compare: orbit).
The formula is found more frequently in the language of the Church, as in the inscription at the Lateran Basilica, which is: Sacrosancta Lateranensis ecclesia omnium urbis et orbis ecclesiarum mater et caput ("Most Holy Lateran Church, of all the churches in the city and the world, the mother and head".
In the 4th century, Pope Damasus I wrote in a letter to the bishops of Illyricum: Unde iustum est, omnes in Universo Romanorum Orbe Doctores legis, ea, quae legis sunt, sapere, et non fidem doctrinis variis maculare ("Wherefore it is just that all the teachers of the law in the universe of the Roman world should be wise in the things of the law, and not to tarnish the faith with various doctrines").
The ritual of the papal blessing Urbi et Orbi developed in the 13th century during the reign of Pope Gregory X, who consulted Niccolò and Maffeo Polo before his election.
The Urbi et Orbi address and blessing is the most solemn form of blessing in the Catholic Church, and is reserved for the most solemn occasions. These occasions include Easter, Christmas, and the proclamation of a newly elected pope concluding a conclave.
Urbi et orbi blessings are usually given from the central loggia of Saint Peter's Basilica in Vatican City, at noontime, and are broadcast worldwide through the European Broadcasting Union and other linkups. The address concludes with greetings in many languages in relation to the feast celebrated.
The Roman Catholic Church grants a plenary indulgence by the willful grace and intent of the pope, on the usual conditions, to those who "devoutly receive" the blessing that the pope imparts Urbi et Orbi.
For any ordinary plenary indulgence, the conditions are:
Gaining a plenary indulgence requires that a baptized Roman Catholic must also exclude any attachment to sin, even venial sin.
Since 1985, this indulgence is granted not only to the people in Saint Peter's Square, but also to those who though unable to be physically present, "piously follow" it by radio or television.
This is now extended to all who receive the papal blessing over the Internet ("the new communications medium"), since the blessing is preceded by an announcement by a cardinal (usually the cardinal protodeacon): "His Holiness Pope N. grants a plenary indulgence in the form laid down by the Church to all the faithful present and to those who receive his blessing by radio, television and the new communications media. Let us ask Almighty God to grant the Pope many years as leader of the Church and peace and unity to the Church throughout the world."
On 27 March 2020, Pope Francis imparted an extraordinary Urbi et Orbi blessing in order to pray for the end of the COVID-19 pandemic. He stood in a deserted Saint Peter's Square. For this blessing, the Apostolic Penitentiary loosened the requirements to receive the Eucharist and go to confession, due to the impossibility for people affected by lockdowns and suspension of liturgies. The Salus Populi Romani image and a crucifix from the church of San Marcello al Corso – both seen as miraculous – were brought to the square for the occasion. The Pope performed the blessing as a Benediction of the Blessed Sacrament.
From Pope Paul VI to Pope Benedict XVI, after delivering their Urbi et Orbi message, the pope would greet the different nations in their native languages. The pope typically began by saying: "To those who listen to me, I address a cordial greeting in the different language expressions." Pope Francis has since stopped this practice.
Prior to the occupation of Rome by the army of the Kingdom of Italy (20 September 1870), this blessing was given more frequently and at specific basilicas at Rome:
On the occasion of a Holy Year the pope gave the blessing on other occasions too for the benefit of pilgrims. In the jubilee year of 1650 Pope Innocent XI did so at Epiphany, Pentecost, and All Saints. He and later popes gave such special-occasion blessings from the balcony of the Quirinal Palace, which was then the papal residence.
Pope Pius IX, who considered himself a "prisoner in the Vatican" gave the solemn blessing of Urbi et Orbi from the balcony of the Quirinal Palace.
It is the motto of Long Island University.