A former papal diplomat - charged with the sexual abuse of boys - has been admitted to hospital ahead of his trial at the Vatican.
Jozef Wesolowski is being treated in intensive care as his trial was set to open on Saturday.
The judge is expected to immediately adjourn the case to a later date.
The 66-year-old faces charges that he sexually abused shoeshine boys in the Dominican Republic and possessed child pornography.
If he is found guilty, he could face up to ten years in prison.
His trial has been seen as a high-profile way for Pope Francis with to make good on pledges to punish high-ranking churchmen involved in sex abuse of minors, either by molesting children or by systematically covering up for priests who did.
Mr Wesolowski, from Poland, was discretely recalled to the Vatican by Pope Francis in 2013 after allegations surfaced in an investigative TV programme in the Dominican Republic.
In the programme, journalist Nuria Piera interviewed men who claimed they were abused by the archbishop. The programme also aired secretly filmed footage allegedly showing Mr Wesolowski walking along a beachfront known to be used by child prostitutes.
He was defrocked, or laicised, at a 'canonical' or religious trial at the Vatican in late 2013, but his criminal trial represents the first of its kind.
Anne Barrett Doyle, from BishopAccountability.org which documents sexual abuse within the Catholic church, said: "It's very important that this apparently veracious predator be investigated arrested and tried."
