Cardinals swore an oath of secrecy and locked themselves inside the Sistine Chapel on Tuesday, starting a conclave that they hope will elect a new pope who can heal divisions inside Roman Catholicism's hierarchy while tending to its 1.2 billion faithful.

The procession of cardinals into the chapel capped a day of carefully scripted events designed to showcase unity among the princes of the church as well as their continuity with centuries of tradition. But the rituals came against a backdrop of stark divisions over what kind of leader Catholicism needs to guide it in its 21st century.

In the evening, black smoke rose from the chapel, signaling that cardinals didn't reach the two-thirds majority needed to choose a new pope in their first vote. The voting was set to continue on Wednesday morning.

In recent weeks, cardinals from around the world have publicly vented grievances over the opaque governance of the Roman Curia, the Vatican's scandal-plagued administrative body, pitting themselves against a coterie of colleagues who are longtime Vatican insiders.

Pope Benedict XVI's resignation