Ratzinger, Battista Re and Angelo Sodano are just three of the names of the many high-ranking Vatican figures who are thought to have serious chances at becoming the Roman Catholic Church's next pontiff.

Though their names are among the many being whispered in the Vatican hallways as possible papal successors, prominent advisors all lose their powers upon the pope's death and the cardinal camerlengo or chamberlain, Cardinal Eduardo Martinez Somalo, becomes the temporary head of the church.

The pope's death immediately sets into motion a historic chain of events to elect a successor and prevents any risk of division in the Roman Catholic Church.

Successor elected in complete secrecy

Whoever takes over the throne in Rome and the 1.1 billion member Catholic Church is elected 15 to 20 days after the pope's death in a secret conclave meeting of up to 120 cardinals under the age of 80 in the Vatican's Sistine Chapel under Michelangelo's awesome fresco of the Last Judgment, according to a law adopted in 1975.

Opinions are split as to whether the current 117 such cardinals, nearly 100 of whom were appointed by John Paul II, will continue Karol Wojtyla's conservative legacy or try to reflect the profound changes that have taken place in the Church in choosing a successor, who is most likely to come from among the cardinals themselves.

Age and nationality key issues

If the cardinals are reasonably unanimous about the policies they want the Church to follow, they are likely to elect a young man to carry out these policies far into the future. If they cannot agree on policies, they are more likely to choose an elderly candidate as a temporary measure.

Under John Paul II, the college of cardinals has become so internationalized and decentralized that the next pope could come from anywhere in the world, although there is a powerful sentiment to return to tradition and elect an Italian.

If this were to happen, strong candidates would include archbishops Dionigi Tettamanzi, 70, of Milan, Angelo Scola, 63, of Venice, Tarcisio Bertone, 70, of Genoa, Angelo Sodano, 77, and Battista Re, 71.

German Cardinal Joseph Ratzinger (photo), 77, head of the Vatican's Congregation for the Doctrine of the Faith, is also seen as a potential pontiff.

Church on rise in Africa, South America

If the cardinals decide on a non-Italian candidate, the field is wide open.

With church congregations rising across Africa, southern Asia and Latin America, observers see a global church that is increasingly orientated towards the south and away from its European heartland.

Africa, where the Church is facing competition from Islam and other confessions, has a strong candidate in Cardinal Francis Arinze from Nigeria, 72, who heads the Vatican congregation for divine worship. There are also four possible candidates from Latin America.

By church estimates the number of Catholics in Africa has nearly doubled, from 50 million to 90 million, in the past 20 years. More than two thirds of Catholics are now estimated to come from the "global south."

Holy Spirit said to guide decision

In the past, the cardinal electors had to live in frugal quarters in the palace itself, but this time they will stay in hotel-style rooms in a Vatican hostelry called Santa Martha House. The staff assigned to serve them, including a doctor, a cook and several nuns, are sworn to secrecy on pain of excommunication from the church.

A key factor often ignored by outsiders is that the cardinals believe that the invisible presence of the Holy Spirit is with them in the Sistine Chapel guiding their decision.