Pope Francis is facing an unprecedented rebellion from conservative cardinals who are furious at his apparent attempts to relax the Catholic Church's ban on remarriage after divorce.

Four cardinals wrote to the Pope challenging his teaching after his statement in September that divorced and remarried Catholics can in "some cases" receive Holy Communion without living as "brother and sister" and without getting an annulment.

Pope Francis had written to bishops in his home country of Argentina offering his own interpretation of Amoris Laetitia, his exhortation that published after the two synods on the family.

The synods were dominated by controversy over the status of divorced and remarried Catholics.

The Church is divided between those say there can be no flexibility over the teaching that marriage is for life and those who argue that to exclude people communion even where they were the innocent party in a marriage breakdown is cruel.

Pope Francis, whose Jubilee Year of Mercy has just ended, wants to make the Church more compassionate and has argued: "No one can be condemned forever". 

The four cardinals, American Raymond Burke, Italian Carlo Caffarra and Germans Walter Brandmüller and Joachim Meisner, wrote to Pope Francis in September and have this week published the letter because they received no reply.

They call on Pope Francis to to "resolve the uncertainties and bring clarity". The four cardinals accuse the Pope of publishing "divergent" and "conflicting" advice, thereby provoking "uncertainty, confusion, and disorientation among many of the faithful." 

Conservative bloggers in response to the controversy have become vituperative about the Pope, who throughout most of the rest Christendom and beyond has soared to unprecedented levels of popularity.

Rorate-Caeli comments: "Bergoglioland has finally reached full Banana Republic status."

Commentator Father John Zuhlsdorf writes: "I'd be willing to bet that The Four are merely the tip of the spear. I'd wager that they represent a large gang of quiet Cardinals who want answers, but because they are presently in curial or diocesan positions they are hesitant to raise their heads too high."

Conservative Catholic Chris Gilligrand told Christian Today: "This is a low point in the modern Papacy, a Pope who seems unable to articulate the content of the Catholic Faith."

Chiesa Espresso quotes Matthew's Gospel at the Pope: "If your brother does not listen, take with you two or three witnesses. If he refuses to listen to them, tell the assembly".

Cardinal Burke told the National Catholic Register the letter was not political but an "act of charity". He said: "The initiative is aimed at one thing only, namely the good of the Church, which, right now, is suffering from a tremendous confusion on at least these five points."

He said Jesus taught: "He who divorces his wife and marries another commits adultery."

But if a person in an "irregular marriage union", which in these cases means a civil and not a Catholic marriage, can receive holy Communion, then either marriage really is not indissoluble or holy Communion is not communion with the Body and Blood of Christ.

But both of these contradict Church teaching.

He says: "It is the duty in such cases, and historically it has happened, of cardinals and bishops to make clear that the Pope is teaching error and to ask him to correct it."