Spain's leading archbishop, Cardinal Antonio María Rouco, yesterday denounced the new socialist government, saying its policies were taking the country back to medieval times, when Muslim invaders swept across the Straits of Gibraltar.
His comments came after the government's decision to cancel the reintroduction of compulsory religious classes and to find ways of financing other faiths, including Islam, with public money.
"Some people wish to place us in the year 711," Cardinal Rouco said. "It seems as if we are meant to wipe ourselves out of history."
The Catholic church is coming to terms with a sudden and dramatic dwindling of its power following the socialists' victory, in March, over the conservative, pro-Catholic People's party of the former prime minister José María Aznar. Mr Aznar's government had planned to make religion a compulsory exam subject.
But the socialists have already announced that the law reintroducing compulsory religion lessons, a feature of the Franco dictatorship, will be scrapped.
Cardinal Rouco also expressed concern that, as Spain begins to debate rewriting its 1978 constitution, references to the Catholic church, with which the state is obliged to "maintain relations of cooperation", could be diluted.
The Catholic church main tained the right to appoint and sack religious teachers in state schools in an accord with the Vatican in 1979. There is now pressure on the socialist government to change the accord and take away a right under which, in recent years, teachers have been sacked for having too colourful a social life or for marrying divorcees.
"It would be wrong to question, limit or scrap it [the accord]," said Cardinal Rouco.
Spain's Roman Catholic establishment has also been upset by the government's announcement that it will legalise gay marriage at the beginning of next year. Common law marriages are also set to be recognised.
The socialists are also planning to relax Spain's rules on abortion, where women must find a doctor prepared to say that they will suffer physical or psychological damage if they do not abort.
In a further blow to the church's power over the political establishment, the government is also encouraging stem-cell research with human embryos, something that Mr Aznar's government had also banned.
The justice minister, Juan Fernando López Aguilar, was due to meet Jewish, Muslim and Protestant leaders this week to discuss ways in which they might be financed by the state, according to ABC newspaper yesterday.
At present, only the Roman Catholic church can receive donations from Spanish tax payers, who can indicate on their tax declaration that they want to make a contribution.
Protestant leaders have long complained that their churches are treated as a second-class form of Christianity by the Spanish state.
Despite this, the number of Protestants is growing in Spain. Islam is also on the rise, with immigrants from north Africa and domestic converts building new mosques.
The Catholic church, meanwhile, is being forced to close monasteries and convents and import priests from South America as what was once a powerful political and social force slowly declines.
Only 18% of Spaniards currently declare themselves to be practising Roman Catholics, compared with 98% 50 years ago.
The Arab conquest of Spain started when a Moorish army led by Tariq bin Ziyad swept across the Straits of Gibraltar in 711. It took them just seven years to establish control of almost the entire country, as well as what is now Portugal.
It took the Christians several centuries to reconquer Spain. The last Moorish king, Boabdil, did not leave Granada until 1492.
The Moors left behind them some of Spain's most important historic monuments, including the Alhambra palace in Granada and the Great Mosque in Cordoba.