Pope Francis, who presided over the Roman Catholic Church and its estimated 1.4 billion followers for 12 years, died April 21.

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.