"Let us pray for the cardinals who are to elect the Roman pontiff, " read one of the prayers during the Mass.

NPR: Cardinals Celebrate Mass Before Entering Conclave

If the ballot has elected a new Roman Pontiff, white smoke rises.

FORBES: How Is A New Pope Elected?

This same Cardinal Dean will also announce to the city of Rome and to the world the name of the new Roman Pontiff.

FORBES: How Is A New Pope Elected?

Peter's Basilica, where they celebrated a Mass "for electing the Roman pontiff, " a ceremony that sets the tone for cardinals voting in the conclave.

WSJ: Black Smoke Signals No Pope Yet

"We promise and swear to observe with the greatest fidelity and with all persons, clerical or lay, secrecy regarding everything that in any way relates to the election of the Roman pontiff, " the cardinals said under the looming fresco of Michelangelo's Last Judgment.

WSJ: Black Smoke Signals No New Pope

Though Benedict left the rules greatly untouched, experts on the Church's constitution will comb through the section on the "Vacancy of the Apostolic See and the Election of the Roman Pontiff" (how to elect a new pope when the office is vacant) and interpret proper protocol for the election.

CNN: Smoke signals: How is a new pope elected?

The new pontiff, the first from Latin America, has called for the Roman Catholic Church to be closer to ordinary people, especially the poor and disadvantaged.

BBC: Pope Francis to wash feet of prisoners in pre-Easter Mass