For the world's press amd millions catholics there is no front-runner, no indication how long voting will last and no sense that a single cardinal has what it takes to fix the church's many problems.
On the eve of the vote, cardinals offered wildly different assessments of what they were looking for in the next pontiff and how close they were to a decision.
It was evidence that Benedict XVI's surprise resignation has continued to destabilise the church leadership and that his final appeal for unity may go unheeded, at least in the early rounds of voting.
Cardinals held their final closed-door debate yesterday over whether the church needs a manager to clean up the Vatican's bureaucratic mess or a pastor to inspire the 1.2 billion faithful in times of crisis.
The fact that not everyone got a chance to speak was a clear sign that there was still unfinished business on the eve of the conclave.
"This time around, there are many different candidates, so it's normal that it's going to take longer than the last time," Cardinal Francisco Javier Errazuriz of Chile said.
"There are no groups, no compromises, no alliances, just each one with his conscience voting for the person he thinks is best, which is why I don't think it will be over quickly."
None of that has prevented a storm of chatter over who is ahead.
The buzz in the papal stakes swirled around Cardinal Angelo Scola, an Italian seen as favoured by cardinals hoping to shake up the powerful Vatican bureaucracy, and Brazilian cardinal Odilo Scherer, a favourite of Vatican-based insiders intent on preserving the status quo.
Cardinal Scola is affable and Italian, but not from the Italian-centric Vatican bureaucracy called the Curia. That gives him clout with those seeking to reform the nerve centre of the church that has been discredited by revelations of leaks and complaints from cardinals in the field that Rome is inefficient and unresponsive to their needs.
Cardinal Scherer seems to be favoured by Latin Americans and the Curia. He has a solid handle on the Vatican's finances, sitting on the governing commission of the Vatican bank, as well as the Holy See's main budget committee.
As a non-Italian, the archbishop of Sao Paulo would be expected to name an Italian as secretary of state - the Vatican number two who runs day-to-day affairs - another plus for Vatican-based cardinals who would want one of their own running the shop.
The pastoral camp seems to be focusing on two Americans, New York archbishop Timothy Dolan and Boston archbishop Sean O'Malley. Neither has Vatican experience.
Canadian cardinal Marc Ouellet is well-respected, stemming from his job at the important Vatican office that vets bishop appointments.
If the leading names fail to reach the 77 votes required for victory in the first few rounds of balloting, any number of surprise candidates could come to the fore as alternatives.
It all starts with the cardinals checking into the Santa Marta residence on the edge of the Vatican gardens.
At 10am local time the dean of the College of Cardinals, Angelo Sodano, led the celebration of the "Pro eligendo Pontificie" Mass - the Mass for the election of a pope - inside St Peter's Basilica, joined by the 115 cardinals who will vote.
This is followed with a procession into the Sistine Chapel, with the cardinals intoning the Litany of Saints, the hypnotic Gregorian chant imploring the saints to help guide their voting. After another chant calling on the Holy Spirit to intervene, the cardinals take the oath of secrecy, followed by a meditation delivered by elderly Maltese cardinal Prosper Grech.
Then the master of papal liturgical ceremonies gives the order "Extra omnes" - "Everyone out" - and all but those taking part in the conclave leave the chapel's frescoed walls.
During the voting that ensues, each cardinal writes his choice on a rectangular piece of paper inscribed with the words "Eligo in summen pontificem" - Latin for "I elect as Supreme Pontiff".
Holding the folded ballot up in the air, each approaches the altar and places it on a saucer, before tipping it into an oval urn, as he intones these words: "I call as my witness, Christ the Lord, who will be my judge that my vote is given to the one who, before God, I think should be elected."
After the votes are counted, and the outcomes announced, the papers are bound together with a needle and thread, each ballot pierced through the word "Eligo". The ballots are then placed in a cast-iron stove and burned with a special chemical.
That is when all eyes will turn to the 6ft copper chimney atop the Sistine Chapel to pipe out puffs of smoke to tell the world if there is a new pope.
Black smoke means "not yet" - the likely outcome after round one. White smoke means the 266th pope has been chosen.
The first puffs of smoke should emerge some time around 8pm. If they are black, voting will continue, four rounds each day, until a pope is elected.
The next pope will face a church in crisis: Benedict spent his eight-year pontificate trying to revive Catholicism amid the secular trends that have made it almost irrelevant in places like Europe, once a stronghold of Christianity.
Clerical sex abuse scandals have soured many faithful and competition from rival evangelical churches in Latin America and Africa has drawn souls away.
Closer to home, leaks of papal documents last year exposed ugly turf battles, allegations of corruption and even a plot purportedly orchestrated by Benedict's aides to out a prominent Italian Catholic editor as gay.
Papal Conclaves over the past 100 years
Over the past century, no conclave has lasted more than five days and the fastest vote was for Pope Pius XII.
Twice prelates from North America missed the vote because they could not get to Rome in time, and a Hungarian cardinal sat out two conclaves because he was holed up in the US Embassy in Budapest seeking asylum.
These are the results of previous conclaves in the last 100 years:
:: July 31-August 4, 1903: Italian Cardinal Giuseppe Sarto (Pius X) elected on seven ballots over four days. Sixty-two of 64 cardinals participated.
:: August 31-September 3, 1914: Italian Cardinal Giacomo della Chiesa (Benedict XV) elected on 10th ballot on third day. Fifty-six of 65 cardinals participated. Cardinals from Boston, Baltimore and Quebec arrived after the election.
:: February 2-6, 1922: Italian Cardinal Achille Ratti (Pius XI) elected on 14th ballot on fifth day. Fifty-three of 60 cardinals participated. Cardinals from Boston, Philadelphia and Quebec arrived too late.
:: March 1-2, 1939: Italian Cardinal Eugenio Pacelli (Pius XII) elected on third ballot on second day. All 62 cardinals participated.
:: October 25-28, 1958: Italian Cardinal Angelo Roncalli (John XXIII) elected on 11th ballot on fourth day. Fifty-one of 53 cardinals participated. Cardinal Jozsef Mindszenty of Hungary had taken asylum in the US Embassy in Budapest, and Yugoslav Cardinal Alojzije Stepinac was under house arrest.
:: June 19-21, 1963: Italian Cardinal Giovanni Battista Montini (Paul VI) elected on sixth ballot on third day. Eighty of the 88 cardinals participated. Cardinal Mindszenty was still in US Embassy asylum.
:: August 25-26, 1978: Italian Cardinal Albino Luciano (John Paul I) elected on fourth ballot on second day. A total of 111 cardinals from 49 nations and territories took part and three were absent because of illness; 15 cardinals could not join under new rule limiting vote age to under 80.
:: October 14-16, 1978: Polish Cardinal Karol Wojtyla (John Paul II) elected on eighth ballot on third day to become first non-Italian pope since Adrian VI (1522-1523). A total of 111 cardinals from 49 nations and territories took part.
:: April 18-19, 2005: German Cardinal Joseph Ratzinger (Benedict XVI) elected on fourth ballot on second day. A total of 115 cardinals from 52 nations and territories took part.
In the papal conclave that begins today, 115 cardinals will elect the next pope
All of them were created either by Benedict XVI or Pope John Paul II, ensuring that whoever is chosen will follow in their conservative line.
Here is their geographic distribution:
EUROPE: 60 electors, or more than half the bloc. Italy alone claims 28, followed by Germany with six.
NORTH AMERICA: 14 electors, with 11 from the United States and three from Canada.
LATIN AMERICA: 19 electors. Brazil has the most with five.
AFRICA: 11 electors, with Nigeria counting two.
ASIA: 10 electors, with India counting five.
OCEANIA: One elector: Sydney Cardinal George Pell.