Last week's police raid in Belgium which broke up a meeting of the country's Catholic bishops - who were discussing how to deal with the paedophile priest crisis - took the Vatican by complete surprise.
Cardinal Tarcisio Bertone, the Vatican Secretary of State - Pope Benedict's number two - was furious when he learned about how the police prevented the bishops from leaving the building where they had been meeting for nine hours, and took away their mobile telephones to prevent them communicating with their staff or with the Vatican.
The police seized files not only from the headquarters of the Catholic Church in Brussels but also took away the laptop belonging to the former head of the Church in Belgium, Cardinal Godfried Danneels.
They also allegedly profaned the tomb of at least one former Belgian cardinal at the cathedral in Mechelen during what seems to have been a frenetic search for possible incriminating documents.
Cardinal Bertone angrily told reporters during a conference he was attending at a Catholic University in Rome that not even communist states dared to treat Church authorities and Church property in this way. He summoned the Belgian ambassador to the Vatican and handed him a formal protest note.
Change of tone
Pope Benedict's own reaction in a letter to the head of the Belgian Church was more measured.
While deploring the way in which the Belgian police had conducted their search for evidence of possible crimes of sex abuse committed by Belgian clergy, he said he was happy to let justice take its course provided the rights of all parties, victims of alleged abuse and accused priests, were respected.
This marked a definite change of tone in Vatican reaction to the clerical sexual abuse crisis which has hit the Catholic Church in Europe and the Americas in recent years and particularly in recent months. Some high-ranking Vatican officials have habitually dismissed media coverage of predator priests as "idle gossip".
Belgium, like many other countries in Europe, has a strong Catholic history but is also subject to strong secular influences. Although the Vatican claims 75% membership of the Catholic Church, regular Sunday Mass attendances have dwindled dramatically in recent years to about 5%.
Last year, the Belgian parliament made a formal diplomatic protest to the Vatican over the Pope's remarks about the use of condoms to combat Aids.
The Pope was on his way to Africa, the continent most seriously affected by Aids, and his remarks aroused a storm of protests - including one by the prestigious British medical journal, the Lancet.
The Vatican rejected the Belgian protest as an "attempt to silence the Pope's moral teaching".
Official relations between the Vatican and Belgium are clouded with a certain ambiguity. No concordat, or treaty, governs relations with the Holy See.
Belgium was part of France between 1795 and 1815, and the Napoleonic Concordat between France and the Vatican signed at the beginning of the 19th Century lapsed after Belgium became an independent state and separated from the Netherlands.
But the practical effects of the Napoleonic Concordat were profound. Its recognition of the Catholic religion paved the way later for full state subsidies for other "recognised religions".
The Belgian state pays salaries for teachers of religion in state schools and stipends and pensions for Catholic clergy and the renovation of Church buildings.
Last week, Pope Benedict appointed a new Bishop of Bruges to replace Roger Vangheluwe - the longest serving bishop in the country who resigned in April after admitting that he had been sexually abusing a boy for years.