Rome (CNN) -- Pope Francis will officially be inaugurated Tuesday as the leader of the world's 1.2-billion member Catholic Church.
Here's what will happen at and around the Installation Mass:
8:45-8:50 a.m. (3:45-3:50 a.m. ET)
Pope Francis leaves the Santa Marta residence, where cardinals stayed for the conclave and where he is living until the papal apartments are ready. He travels to St Peter's Square, where the Inauguration Mass will take place.
About 9:30 a.m. (4:30 a.m. ET)
The pope arrives at St Peter's Square Sacristy (the steps area). He will enter St Peter's Basilica.
He will visit St. Peter's tomb inside St. Peter's Basilica. He will be accompanied by the patriarchs of Catholic Oriental Churches, for a total of 10 people. The pope will pray there.
In the tomb, deacons of the Church will collect two symbols of the papacy -- the fisherman's ring and the pallium.
From the tomb, the pope and cardinals will go in procession through the Basilica and into the Square, accompanied by the processional chant "Laudes Regiae." ("Christ is King")
The deacons will carry the ring and pallium into St. Peter's Square. Catholic tradition holds that St. Peter was martyred in the square, which was Nero's Circus.
Before the Mass starts, Cardinal Jean-Louis Tauran -- the protodeacon who announced the name of the new pope after white smoke last week -- ceremonially presents Pope Francis with the pallium.
Cardinal Godfried Danneels -- the second-ranking cardinal among cardinal deacons, known as the protopriest --d elivers a prayer.
Cardinal Angelo Sodano, the dean of the College of Cardinals, gives the fisherman's ring to Pope Francis.
Six cardinals representing the College of Cardinals (2 cardinals per order) take the pledge of obedience.
About 10:00 a.m. (5 a.m. ET)
Inauguration Mass begins.
It will be the Mass for St. Joseph's Day (officially called the Solemnity of St. Joseph).
The Gospel reading will be in Greek.
Five hundred priests will hand out Communion in St. Peter's Square and in Via Conciliazione (the road leading straight out from the Vatican towards the Castel Sant'Angelo liveshot location.)
The pope will have 180 co-celebrants for the Mass including all the cardinals still in Rome (electors and non), the patriarchs, and also two priests: the Jesuit Superior General and the Franciscan order Superior General.
The pope will give his homily in Italian and, as is his style, it probably will not follow the written text strictly, but will contain improvisations.
11:30 a.m. (6:30 a.m. ET)
The Mass is expected to wrap up. "Te Deum" is to be sung at the conclusion.
After 11:30 a.m. (6:30 a.m. ET)
After the the Mass, the Pope will return to the Basilica and remove his vestment at the altar of the Pieta.
He will proceed at Main altar where he'll receive dignitaries and heads of state.