Watch: Cardinals enter conclave to decide who follows Pope Francis

Roman Catholic cardinals have begun the task of electing a new pope, locking themselves away from the world until they choose the man they hope can unite a diverse but divided global Church.

In a ritual dating back to medieval times, the cardinals filed into the Vatican's frescoed Sistine Chapel after a public Mass in St Peter's Basilica and started their secret conclave for a successor to Pope Francis, who died last month.