Pope Francis, battling double pneumonia in hospital for two weeks, had an "isolated breathing crisis" on Friday and received "non-invasive mechanical ventilation" to help him breathe, the Vatican said in a statement.

The Vatican, though, made alternative plans for Ash Wednesday next week, making clear Francis still had a long road ahead. Cardinal Angelo De Donatis, a Vatican official and former vicar of Rome, will preside over the March 5 ceremony and procession that inaugurates the church’s solemn Lenten season leading up to Easter in April.

Amid ongoing health issues facing Pope Francis, here is the process by the Vatican when a pontiff passes away.