Hundreds of thousands of people are expected to converge on St. Peter's Square March 19 for the installation of Pope Francis, including large delegations from Argentina and Italy.

The ceremony is formally titled "The Inauguration of the Petrine Ministry of the Bishop of Rome" and begins with a visit to the tomb of St. Peter.

The largest delegations will be coming from Argentina and Italy. President Cristina Fernandez de Kirchner is leading a group of 19 people from the Argentinian government, while President Gorgio Napolitano is bringing 16 officials on behalf of Italy.

Pope Francis has asked for a few changes to the ceremony, but it will not be significantly different than Benedict XVI's installation in 2005.

One interesting change will be that the Gospel will be sung only in Greek, whereas in the past it was also sung in Latin, signifying the Eastern and Western branches of the Church.

Pope Francis' inauguration will begin with him making his way through St. Peter's Square in the popemobile or the open-air Jeep.

After that he will visit St. Peter's tomb under the main altar of the Vatican basilica.

He will be joined at the tomb by the patriarchs of the Eastern Catholic Churches, who will carry his pallium – a circular stole of white wool that evokes the image of the Good Shepherd –into St. Peter's Square. The patriarchs will also carry his Fisherman's ring out to the square.

The pallium is the same one that was used by Benedict XVI, while the ring belonged to Pope Paul VI. The ring was designed by the famous Italian jeweler Henry Manfrini and was offered to the Pope by Cardinal Giovanni Battista Re.

Vatican press office director Father Federico Lombardi specified March 18 that it is not known whether Paul VI ever wore the ring.

Following the conferral of the pallium and ring, there will be a brief rite in which six cardinals – two from each order – will offer their obedience to Pope Francis.

The concelebrants for the Mass will be all of the cardinals, the Eastern Catholic patriarchs, and two priests.

The priests will be Franciscan Father José Rodríguez Carballo and Jesuit Father Adolfo Nicolás, in their roles as president and vice president of the Union of Superiors General, respectively.

Since March 19 is the Feast of Saint Joseph, the readings and Mass parts for that solemnity will be used.

The celebration will have delegations from 132 separate entities, including 33 Christian churches, 16 Jewish representatives, and 31 heads of state.

Significantly, the Orthodox Patriarch Bartholomew I will attend the inauguration for the first time since the Great Schism of the Church into Eastern and Western confessions in 1054.

Papal master of ceremonies Monsignor Guido Marini expects the inauguration and Mass to be finished by 11:30 a.m.