Roman Catholic cardinals have gathered in Rome ahead of a secretive conclave to choose a new pope with no clear frontrunner in sight.
The 115 Roman Catholic priests known as Cardinal Electors will begin the daunting task of electing the successor of Benedict XVI who resigned citing health issues.
Their deliberations will take place in what is probably the most famous of the Vatican's buildings - the Sistine Chapel.
They are set to hold a first round of voting late Tuesday afternoon.
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The cardinals will be completely cut off - banned from any communication with the outside world and bound by a strict oath of secrecy on pain of excommunication - until they have chosen one in their midst to be pope.
The preists held their final closed-door debate on Monday over whether the church needs more of a manager to clean up the Vatican's bureaucratic mess or a pastor to inspire the faithful in times of crisis.
Around 90 Vatican staff, including cooks, drivers and security guards, took part in a ceremony at the Vatican's Paolina Chapel on Monday.
The staff, who are assisting the cardinals, have pledged not to reveal what they might hear in the coming days.
The tradition of holding conclaves goes back to the 13th century when cardinals were locked into the papal palace in Viterbo near Rome by the angry faithful because they were taking too long to make their decision.
That conclave still dragged on for nearly three years but the rules have been reworked since then and the longest conclave in the past century - in 1922 - lasted only five days. Benedict's election took just two days.
Benedict stunned the world on February 11, announcing that he no longer had the strength of body and mind to keep up with a fast-changing modern world shaken by vital questions for the Roman Catholic Church.
In a series of emotional farewells, 85-year-old Benedict said he would live "hidden from the world" and wanted only to be "a simple pilgrim" on life's last journey.
Vatican experts have said the German's decision, which makes him only the second pope to resign by choice in the Church's 2,000-year history, could mean future popes will also step down once their strengths begin to fail them.
Cardinals prayed for divine guidance at their last Sunday masses before the conclave in churches across Rome.