VATICAN CITY (Reuters) - Cardinals voting to elect a new pope this week will take inspiration from some of the world's greatest and most famous works of art in the 500-year-old Sistine Chapel.
Shut off from the outside world, the 115 cardinals will cast their ballots in a chapel which has Michelangelo's soaring Last Judgment on one wall, and his depiction of the hand of God giving life to Adam above them.
Roman Catholics around the world will focus their attention on a humble chimney on the roof of the chapel which will tell of the progress in selecting a new pope - black smoke for deadlock, and white to tell the world that a new pontiff has been chosen.
The chapel, completed in the 16th century, sees 20,000 visitors pour through on an ordinary day, carefully watched by Vatican museum guards as they try to sneak banned photographs.
This week, the chapel will fall silent but for the prayers of the "princes of the church" and the quiet footsteps of their few assistants, sworn to secrecy about what they witness in a conclave expected to last a few days.
The chapel has been used to hold the conclave since 1484, after the death of the man from whom the church takes its name, Pope Sixtus IV, who helped begin the artistic renaissance of the following century by gathering craftsmen around him and supporting their works.
On that occasion, the cardinals elected Innocent VIII, a man remembered in the Encyclopaedia Britannica as a pope whose nepotism towards his two illegitimate children was "as lavish as it was shameless".
This was the era when Roman baronial families fought viciously to win the papacy and the vast access to wealth that came with it.
The spirit of the 16th-century Renaissance can be sensed from the exuberant work of Michelangelo, who toiled for four years on a special scaffold before finishing the ceiling frescoes in 1512.
Michelangelo returned to the chapel more than 20 years later to work on the vast Last Judgment on the chapel's altar wall.
The 160-square-metre (1,722-square-foot) wall is an awe-inspiring display of saints floating up to paradise welcomed by trumpeting angels while the damned plunge into the fires of hell, where hungry serpents await them.
The artist was immediately accused of immorality and obscenity for depicting his sensuous and tortured nudes in a church when the work was unveiled in 1541.
After his death, a law was passed to cover up the offending genitalia with "modesty breeches", some of which remain in place after a recent restoration.
More than 5 million people pour through the chapel each year - leading the Vatican to warn it may limit access to prevent damage to the artistic treasures.
At a vespers service last year to commemorate the 500th anniversary of the ceiling frescoes, Pope Benedict seemed to agree on the need for greater calm in the chapel.
"When contemplated in prayer, the Sistine Chapel is even more beautiful, more authentic. It reveals itself in all its richness," he said.
From 1980 to 1994, during the papacy of John Paul II, the chapel benefited from one of the most ambitious restoration projects in the world - it stripped away centuries of dirt and soot that had darkened the frescoes.
The results divided art experts and tourists, with some criticizing the dazzling colors as too bright.
The chapel, lit on either side by high windows, has side walls decorated by Pietro Perugino, Sandro Botticelli and Domenico Ghirlandaio, each famous in his own right.
Once the conclave is over, tourists will flock back to the chapel, of which German writer Goethe remarked: "Without having seen the Sistine Chapel, one can form no appreciable idea of what one man is capable of achieving."
Reporting by Naomi O'Leary; editing by Keith Weir/Mark Heinrich