The Vatican's papal conclave to choose a new spiritual leader for the world's 1.4 billion Catholics is governed by procedures and rituals that have evolved over centuries.
But the result of the election will be influenced by arithmetic unique to this year's exercise: 133 Cardinal electors A record number of churchmen are eligible to vote in conclave.
There are 135 who meet the criteria -- to be a cardinal under the age of 80 -- but only 133 are to take part in the vote, with two said to be too ill to attend.
This is up from 115 during the last two conclaves in 2005 and 2013.
