The Church of England owes its creation to a royal spat over divorce and remarriage: Henry VIII's break with the Vatican after the pope refused to grant the monarch dispensation to wed his lover.
Now, nearly five centuries later, questions over another wedding are pulling at Anglican unity - the planned marriage of Camilla Parker Bowles and Prince Charles, the first in line to inherit the throne and become the next titular head of the church.
Conservative groups complain the scheduled April 8 civil ceremony and post-vows service by the Archbishop of Canterbury - although fully legal - run counter to Church of England traditions against remarriage and will deepen rifts at a delicate time for the world's 77 million-strong Anglican Communion, which includes Episcopalians in the United States.
Anglicans are struggling with serious quandaries over doctrine and structure. Chief among them: whether to sanction the ordination of gay clergy, give blessings to same-sex unions and allow women priests to become bishops. Fresh debates are expected at a global gathering of Anglican leaders beginning Monday in Northern Ireland, where the Episcopal Church also could be sanctioned for consecrating a gay bishop.
The wedding plans add another point of friction, conservative leaders say.
"We know there's a head of steam to liberalize the church already," said George Curry, chairman of the Church Society, comprising tradition-minded Anglican clergy and lay members in Britain. "There are theological questions at stake. Charles is now one of them."
Actually, it's the bride-to-be who appears to be deeper in the religious quagmire.
Her ex-husband, Andrew Parker Bowles, is alive. For conservatives, this is an affront to Anglican tenets; whereas Charles, as a widower, is free to remarry.
"It has grave consequences for the future of the church," delegate Allan Jones told the Church of England's governing General Synod, which met this week in London.
A statement from another conservative group, the Evangelical Alliance, applauded plans to give the relationship "a more moral footing." But it noted broad reservations persist.
"The couple's previous divorces, their documented adultery and the nature of their extramarital relationship up to this point do present difficulties for many of our Anglican members and others with respect to Charles' suitability to govern the Church of England," said a statement from the London-based alliance, which claims 1 million members from various denominations.
The Church of England disapproves of the remarriage of divorced people in church except under special circumstances. There are no annulments - as possible with Roman Catholics - that open the way for a new, church-sanctioned wedding.
But there are sidesteps available for Anglicans. The royal wedding is taking the most popular one: having a civil service and a later blessing by a priest.
"What the Archbishop of Canterbury is doing is perfectly legal, so you could say it's not pushing the envelope," said the Rev. Gerald Bray, an Anglican theologian at the Beeson Divinity School in Birmingham, Ala. "But there's something more subjective: It may be legal, but is it wise?"
Bray predicted it "won't be encouraging for people who want to encourage traditional moral standards."
Some already feel on the defensive.
In 2002, the General Synod loosened rules on remarriage in the church. Parish priests were given discretion to deem whether the couple met the new guidelines. Among the caveats: The new relationship shouldn't be the cause of breaking up the previous marriage - which is precisely what the supporters of the late Princess Diana claim.
But the Archbishop of Canterbury, Rowan Williams, insisted there was no reason for Buckingham Palace to seek loopholes for Charles.
"These arrangements have my strong support and are consistent with Church of England guidelines concerning remarriage," said a statement from the archbishop.
It's a clear reflection of a broad attitude shift in the church since one of the most stunning moments in Britain's royal history: the decision by King Edward VIII in 1936 to abdicate in order to marry a twice-divorced American, Wallis Simpson.
Geoffrey Wainwright, a professor specializing in Protestant affairs at Duke Divinity School, said the upcoming wedding also may revive questions about the Church of England's constitutional ties to the monarchy, which can't change doctrine but can in theory influence "temporal" matters. The government's duties - acting in the name of the monarch - include appointing the Church of England's two archbishops and other senior clergy.
"Some theologians would welcome disestablishment for the sake of the church's freedom," Wainwright said. "Others would see it has yet one more sign of the `de-Christianization' of the country."
In the early 16th century, King Henry VIII sought a papal annulment of his marriage to Catherine of Aragon so he could wed his mistress, Anne Boleyn. The pope, however, had already given special dispensation for Henry's marriage to Catherine, who was the widow of his brother. The Vatican was unwilling to admit papal misjudgment and rejected Henry's request. Also, the papacy was under the influence of Henry's nemesis - and Catherine's nephew - Holy Roman Emperor Charles V.
Henry's advisers came up with a radical proposal: Break with Rome and set your own rules. During the 1530s, English clergy and parliament members gradually cut ties with the Vatican and declared Henry the head of the new Church of England.
Henry wasn't through. He was back to the altar after Anne was beheaded for alleged infidelity. He had a total of six wives, including another who lost her head.