Pope Francis is in critical condition. Which means that cardinals from around the world will, more likely than not, soon congregate in the Vatican, to choose his successor. This event, called a conclave, isn’t just the subject of a new political thriller starring Ralph Fiennes; it’s a private ceremony that has long fascinated the religious. Cardinals are sworn to a lifetime of secrecy, after they cast their vote.

But what impact does the pope have on any of our lives, whether we’re Catholic or not?

Today, Barney Zwartz, a senior fellow of the Centre for Public Christianity, and a former religion editor of The Age, on the history of popes who have wrangled with world leaders. And the mixed legacy of Pope Francis.