VATICAN CITY - Electing a pope used to be so difficult cardinals were subjected to isolation, starvation rations and cramped quarters to speed up their choice. Some died before the final ballot.

The search for a new leader of the world's 1.1 billion Roman Catholics, succeeding Pope John Paul, starts on Monday and is expected to last a few days- a far cry from past conclaves that could be long and dangerous ordeals.

The word "conclave", Latin for "with a key", dates back to the protracted election of Celestine IV in 1241, when cardinals were locked up in a crumbling palace by Roman noble Matteo Orsini.

Aimed at forcing a decision in the sweltering August heat, the lock-up led to the death of one of the 10 confined cardinals. They eventually reached a decision after two months.

Celestine himself died after only two weeks from the effects of the confinement.

Worse was to come. In 1268, in the town of Viterbo, 85 km (55 miles) north of Rome, cardinals began what proved to be the longest conclave in the history of the Roman Catholic Church.

After two years, restive locals rioted, removing the roof from the palace where the cardinals were gathered- supposedly to let the Holy Spirit join them- and food was restricted.

Conditions were so harsh two cardinals died and a third had to leave due to ill health before the remaining princes of the church eventually chose Gregory X in September 1271.

Gregory was determined the ordeal would never happen again. He was behind a ruling in 1274 that in future cardinals would be locked in a single room with an adjoining lavatory in the late pope's palace within 10 days of his death.

After three days, if no pope was elected, they would be served only one dish for lunch and supper instead of two.

After five days, they would be given only bread, water and a little wine until they decided on a new pontiff.

Hermit Pope

It took more than two years of intermittent conclaves to come up in 1294 with one of the most bizarre choices for a pope.

A deadlock in the conclave ended when Cardinal Latino Malabranca told a meeting of cardinals that a supposedly saintly hermit, Pietro Del Morrone, had prophesied divine retribution for the electors who had failed for so long to find a new pope.

The cardinals agreed to vote for the hermit and Morrone, in his 80s, overcame his amazement by deciding it was God's will. He entered the central Italian town of L'Aquila astride a donkey to be enthroned Celestine V.

But the heady heights of the papal office did not agree with the former hermit and he abdicated after only seven months. A withering reference in Dante's "Inferno" to "he who, through his cowardice, made the great refusal" is believed to refer to him.

Celestine's final act was to restore the conclave rules of 1274, which included a strict ban on communication with the cardinal electors and which have underpinned the principles of conclaves to the present day.

The tribulations of the 13th century were mild compared to some of the elections of earlier times.

In 897, Pope Steven VI ordered the remains of his implacable enemy, Pope Formosus, who had died a year earlier, to be dug up, dressed in papal vestments, propped up on a throne and accused of various crimes.

Unsurprisingly, Formosus was found guilty. His decaying corpse was stripped of its papal vestments and the fingers he used to bless were hacked off before the remains were flung into Rome's Tiber River.

Unfortunately for Steven, the body was retrieved and stories soon spread that Formosus's remains were still working miracles. Steven was deposed in a mob rising, imprisoned and strangled.