THE late Pope John Paul II generated such fear within the Soviet Bloc that spies were ordered to gain information on everything from his underwear to his favourite food.
Karol Wojtyla, who died in 2005 aged 84, remains the only pontiff to have visited Ireland, despite the country boasting one of the world's highest per capita Catholic populations.
Krakow Institute of National Remembrance director, Dr Marek Lasota, said that the future pope was identified as a problem for the Communist authorities as early as 12 months after the end of World War II.
Desperate efforts were made to obtain information on his life, and the lives of other prominent Polish church figures, in a bid to blackmail them into silence or inactivity regarding the regime.
"There was political pressure on the clergy. There were priests which infiltrated the Polish Church. It was a complex situation," Dr Lasota said.
But despite the best efforts of the Warsaw spy chiefs, the future pope was found to be impossible to blackmail, as he lived such a transparent and dedicated lifestyle. Dr Lasota said it was ironic that the Communist regime identified Karol Wojtyla's talents – and the threat he posed to them – years before the church fast-tracked his elevation.
By the time he was appointed a cardinal in 1967, the future Pope John Paul II had been under surveillance by Polish Communist spies for more than 20 years.
Elected pope in 1978, he is widely credited for having played a crucial role in helping dismantle the Soviet Bloc and is revered in Poland for the support he gave the trade union, Solidarity, in its battle against totalitarianism.
The Warsaw regime wanted every aspect of his life monitored and analysed.
Dr Lasota described the kind of information the regime wanted to find out. "For example, what cosmetics does Karol Wojtyla like? When does he shave? Who provides his meals? Who does his laundry? Does he play cards?"