THE NIGHTMARE SCENARIO: How It Could Take Over 2 Years To Select A Pope

Wikimedia Commons Gregory X, eventually chosen as Pope in 1271.

The papal conclave — the election to select the next Pope — begins tomorrow, and the entire world will be watching to see if white smoke comes out of the chimney (Pope found!) or black smoke comes out (no Pope).

People expected the process to take a handful of days.

What's the worst that could possibly happen?

For that, take a look back to the 13th century, when a papal conclave took two years and three months.

The deliberation began in 1268, when Catholic cardinals met in the village of Viterbo — far away from Rome's squalor and diseases — to select a new Pope.

Monsignor Charles Burns, a retired archivist at the Secret Vatican Archives, told ABC News in 2005 that the villagers soon grew angry at how long the process was taking (there was a split between French and Italian factions), and locked the cardinals in a nearby palace (the term "conclave" actually refers to this — it means "with a key").

"The people of Viterbo were so annoyed by this, they said, "OK, we are going to close the cardinals in,' " Burns explained.

In the end, the process went on so long that the villagers tried to stave the cardinals into making a decision, giving them only bread and water. They even tore the roof off the palace in a bid to expose the cardinals to the elements — you can still see tha roof-less palace today:

Eventually the cardinals agreed to a compromise candidate, but there was a final act of obstination — they chose Gregory X, a man who was neither a cardinal or even a priest, as Pope. Gregory, an Italian born as Teobaldo Visconti, was away fighting the crusades. It took 8 months to return.

Of course, it's unlikely that this year's papal conclave will take anywhere near as long — in the 20th century, the longest conclave was just five days. New rules have also been introduced that allow simple majority voting (rather than two-thirds majorities) if a Pope hasn't been found after 12 or 13 days.

However, the conclave of 1268-1271 does have a legacy — don't let the cardinals get too cozy. Gregory decreed in 1274 that Cardinals would only get one meal a day if the conclave went beyond three days, and just bread, water and wine if it went beyond eight, and until recently the cardinals slept inside the Sistene Chapel. Even today, the Vatican's hotel is notably modest.