Pope Francis officially became pontiff Tuesday, in a ceremony that the Vatican said would be short in keeping with the spirit of simplicity exuded by the new pontiff. Here's a timeline of the inauguration, with events updated in the order they occurred.

[Updated at 7:18 a.m. ET]

U.S. Vice President Joe Biden greets Pope Francis.

[Updated at 7:15 a.m. ET]

Spanish Prime Minister Mariano Rajoy greets the pope, as does German Chancellor Angela Merkel.

[Updated at 7:12 a.m. ET]

Controversial Zimbabwean President Robert Mugabe greets the pope at the Vatican's main altar.

[Updated at 7:04 a.m. ET]

A tweet from the pope's account, ?@Pontifex: Let us keep a place for Christ in our lives, let us care for one another and let us be loving custodians of creation.

[Updated at 6:45 a.m. ET]

Argentine President Cristina Fernandez de Kirchner is the first head of state to greet Pope Francis inside St. Peter's Basilica after his Inauguration Mass.

[Updated at 6:43 a.m. ET]

The crowd for the Inauguration Mass of Pope Francis was smaller than expected, Rome police told CNN, declining to give a specific number.

[Updated at 6:41 a.m. ET]

After receiving dignitaries, Francis is expected to go to the Domus Sanctae Marthae for lunch, where the cardinals have been residing for the conclave.

[Updated at 6:27 a.m. ET]

Vatican spokesman the Rev. Federico Lombardi estimates that between 150,000 and 200,000 people turned out in and around St. Peter's Square for the Inauguration Mass on Tuesday.

[Updated at 6:25 a.m. ET]

Francis returns to the Basilica. Later at the main altar, he will receive dignitaries and heads of state.

[Updated at 6:21 a.m. ET]

Mass wrapping up earlier than expected with "Te Deum" being sung. The pope is expected to return to the Basilica and remove his vestment at the altar of the Pieta.

[Updated at 6:14 a.m. ET]

Cardinals receive communion.

[Updated at 6:12 a.m. ET]

A contingency of Syrian flags seen waving in the crowd.