VATICAN CITY, Feb 12 (Reuters) - Cardinals around the world began informal contacts to discuss who should next lead the Church through a period of major crisis and the Vatican said it planned a big send-off for Pope Benedict before he becomes the first pontiff in centuries to resign.
At a Tuesday news conference on how the pope plans to spend the next two weeks before he steps out of the limelight, the Vatican also disclosed that the 85-year-old Benedict has been wearing a pacemaker since before he was elected pope in 2005.
It said no specific illness led him to resign, merely old age and diminishing mental and physical strength.
It also said he would not play any role in the running of the Church after his Feb. 28 resignation.
"The pope has said in his declaration that he will use his time for prayer and reflection and will not have any responsibility for guidance of the Church or any administrative or government responsibility," said Vatican spokesman Father Federico Lombardi.
"This is absolutely clear and this is the sense of the resignation," Lombardi said, adding that he "will not intervene in any way" in trying to influence the choice of his successor.
The shock announcement sent the Vatican scrambling to change venues of some papal activities so that more people can see him before the resignation.
On Wednesday, the pope was to have led a traditional Ash Wednesday service at a small church in Rome but the event has been moved to St Peter's Basilica for what will likely be his last Mass in public.
His last general audience, scheduled for the day before his resignation, has been moved from the Vatican's audience hall, which has a capacity of some 10,000 people, to St Peter's Square, which can hold hundreds of thousands.
After he leaves office on February 28, he will go first to the papal summer residence south of Rome and then to a cloistered convent inside the Vatican walls, exchanging the splendour of his 16th century Apostolic Palace for a sober modern residence.
In mid-March, some 115 cardinals will enter the Sistine Chapel to elect the next leader of the world's 1.2 billion Roman Catholics. Cardinals lose their right to enter a conclave when they turn 80 so the exact number will depend on the day of the start of the conclave.
While the Vatican began preparations for Benedict's last days as pope, Church sources said informal consultations on the phone, at lunches and via e mails have begun among cardinals about what type of leader the next pope should be.
After a string of scandals, Church experts say the cardinals will be looking for someone who is not only a holy man but also a good administrator.
"A lot of cardinals will tell you off the record if you ask them for their private assessment of this pope that personally he was a great man, holy, genuine, honest and humble and that his teachings will stand the test of time," said John Allen, author of several books on the Vatican.
"But they will also say that there was a regime around Benedict XVI that did not know how to make the trains run on time and they were often left to pick up the pieces of bombs that exploded here," he said.
MISHAPS AND MISMANAGEMENT
Benedict has been faulted for putting too much power in the hands of his friend, Secretariat of State Cardinal Tarcisio Bertone. Critics of Bertone, effectively the Vatican's chief administrator, said he should have prevented some papal mishaps and bureaucratic blunders.
Benedict's papacy was rocked by crises over sex abuse of children by priests in Europe and the United States, most of which preceded his time in office but came to light during it.
His reign also saw Muslim anger after he compared Islam to violence. Jews were upset over rehabilitation of a Holocaust denier. During a scandal over the Church's business dealings, his butler was accused of leaking his private papers.
"That was a perpetual frustration for the cardinals outside the Vatican and I think they are concerned that whoever takes over needs to be a little bit more attentive to the internal governance of the Church and of the Vatican in particular," Allen said.
Speculation has grown that the Church could appoint its first non-European leader to reflect the growing weight of regions such as Africa or Latin America, which now accounts for 42 percent of the world's Catholics.
"It could be time for a black pope, or a yellow one, or a red one, or a Latin American," said Guatemala's Archbishop Oscar Julio Vian Morales after Benedict's announcement.
After Benedict's relatively brief papacy, which followed the 27-year pontificate of John Paul II, the cardinals may also be inclined to choose a younger man than Benedict, who was 78 when he was elected.
Whoever is appointed will have to deal with regional issues and the tension between conservative Catholics who have supported Benedict's strictly traditional doctrinal line and others who feel he has stifled change and development.
"In Europe, the Church is seeking a new relationship to society. In many countries in Asia and Africa, it is experiencing an incredible expansion," Archbishop of Vienna Cardinal Christoph Schoenborn said.
Never as popular as the widely beloved John Paul, Benedict was a scholarly theologian with little of the shrewd political instinct which elevated his predecessor to the front rank of world statesmen.
His decision to leave office shocked some Catholics, who felt that a pope should stay in office until the end of his life, and his exit will leave the Church with both a retired and a serving pope for the first time in hundreds of years.
The last pope to leave office willingly was Celestine V, a saintly hermit who served only a few months before abdicating in December, 1294. Another pope, Gregory XII reluctantly abdicated in 1415 to end a dispute with a rival claimant to the papacy. (Reporting by Philip Pullella; Additional reporting by James Mackenzie; Editing by Peter Graff)