There are currently 135 cardinals who are under age 80 and eligible to vote in the conclave, hailing from 71 different countries in the most geographically diverse conclave in history. Already two have formally told the Holy See that they cannot attend for health reasons, bringing the number of men who will enter the Sistine Chapel down to 133.

Pope Francis's death at the age of 88 means the Catholic Church must choose a new leader. Here's how cardinals elect the next pontiff at the conclave.