The 133 cardinal electors due to choose a successor to the late Pope Francis gathered inside the Vatican's Sistine Chapel on Wednesday to begin the secretive, centuries-old ritual known as the conclave to pick a new pontiff.

Simply put, a conclave is the assembly of cardinals that elects a pope. The word itself comes from the Latin "com" and "clavis," meaning "together" and "key," respectively – highlighting the absolute, behind-closed-doors secrecy with which the cardinals conduct their discussions and balloting.