The archbishop of Buenos Aires lives a simple lifestyle, choosing to live in a spartan flat rather than his luxury official residence.

Bergoglio also reportedly uses the bus to get around town, and does his own cooking.

The son of middle-class Italian immigrants, Bergoglio trained as a chemist before deciding to become a priest.

He advocates for the poor, and has won respect for questioning free-market policies he says have left millions of Argentines impoverished.

When he was appointed cardinal in 2001, he persuaded hundreds of Argentines to save the money they would spend on airline tickets if they flew to Rome to celebrate the appointment. Instead, he asked them to donate the money to the poor.

If chosen, he would be the first Jesuit pontiff.

However, his membership in the Jesuit order could work against him, since members are supposed to serve the pope, and avoid Church honours.