The change means conservative Anglicans from around the world will be able to join the Catholic Church while retaining aspects of their Anglican liturgy and identity, including married priests. Until now, disaffected Anglicans had joined the church primarily on a case by case basis.
"The unity of the church does not require a uniformity that ignores cultural diversity, as the history of Christianity shows," said Cardinal William Levada, head of the Vatican's Congregation for the Doctrine of the Faith in announcing the decision.
The spiritual leader of the global Anglican church, Archbishop of Canterbury Rowan Williams, was not consulted about the change and was informed only hours before the announcement. He nevertheless tried to downplay the significance and said it wasn't a Vatican commentary on Anglican problems.
"It has no negative impact on the relations of the communion as a whole to the Roman Catholic Church as a whole," he said in London.
The decision could undermine decades of talks between the Vatican and Anglican leaders over how they could possibly reunite. Although Levada insisted such discussions remain a priority, the Vatican move could be taken as a signal that the ultimate goal of ecumenical talks is to convert Anglicans to Catholicism.
Still, the decision confirmed Pope Benedict XVI's design of creating a unified, tradition-minded Catholic Church - a goal he outlined at the start of his pontificate and has been steadily implementing ever since.
This drive also involved a recent move to rehabilitate four excommunicated ultra-conservative bishops, including one who denied the full extent of the Holocaust, in a bid to bring their faithful back under the Vatican's wing.
Levada made the announcement hours after briefing Williams and Catholic bishops in London about the decision. Notably, no one from the Vatican's ecumenical office on relations with Anglicans attended; Levada said he had invited representatives but they said they were all away from Rome.
Austen Ivereigh, a former adviser to the Catholic archbishop of Westminster, called the Vatican announcement historic because it allowed for the "gradual absorption into the Catholic Church of huge numbers of Anglicans," who are conservative in their theology and liturgy.
Until now, Anglicans had been allowed to join the church primarily on an individual basis. With the new provision, groups of Anglicans from around the world will be able to join new parishes headed by former Anglican prelates, who will provide spiritual guidance to Anglicans who wish to be Catholic. Called personal ordinariates, they will be established within local Catholic dioceses.
The new provision also allows married Anglican priests and even seminarians to become ordained Catholic priests - much the same way that Eastern rite priests who are in communion with Rome are allowed to be married. However, married Anglicans cannot become Catholic bishops.
A model for the future exists in the United States, where a handful of such parishes function - including three in Texas - thanks to a 1980 Vatican decision to accommodate Episcopal faithful and priests who wanted to convert. These parishes use a Vatican-approved Book of Divine Worship, based on the Book of Common Prayer, that includes Catholic and Anglican rituals, said Monsignor William Stetson, who manages the initiative.
The new entity is also modeled on Catholic military ordinariates, special units of the church established in most countries to provide spiritual care for members of the armed forces and their dependents.
In addition, within the Catholic Church there are ancient communities in the Middle East and others in Eastern Europe that follow different rites and allow married priests while remaining loyal to the pope.
The new model doesn't create a new rite, but rather an Anglicanized liturgy within the Latin rite.
Levada said Tuesday's announcement was in response to many requests that have come to the Vatican over the years from Anglicans disillusioned with the progressive bent of the Anglican Communion. Some have already left and consider themselves Catholic but have not found an official home in the 1.1-billion strong Catholic Church.
Levada declined to give exact figures, though he said 30 to 40 bishops had been in touch, accounting for a few hundred would-be converts.
One group, known as the Traditional Anglican Communion, has publicly stated its desire to join the Catholic Church. The group, which split from the Anglican Communion in 1990, says it has 400,000 members in 41 countries, although only about half are regular churchgoers.
"This is a moment of grace, perhaps even a moment of history, not because the past is undone but because the past is transformed," the group's leader, Archbishop John Hepworth said in a statement welcoming the Vatican decision.
Anglicans split with Rome in 1534 when English King Henry VIII was refused a marriage annulment.
Since then, the Anglican Communion, which includes the Episcopalian Church in the United States, has fashioned itself as a kind of big tent of fellowship with a wide variety of worship styles and theological outlooks that include Anglo-Catholics.
It's not known how many Anglicans consider themselves Anglo-Catholic. However, the biggest impact of the Vatican announcement is likely to be felt in England, where the Church of England has been involved in a bitter battle over whether female priests can become bishops. British Anglicans opposed to the ordination of women simply leave and join the Catholic Church.
The announcement is likely to have far less impact in the U.S., where many Anglo-Catholics left the Episcopal Church more than a decade ago. More recently, four theologically conservative Episcopal dioceses and dozens of individual parishes broke away and formed a rival church in North America.
The Episcopal Church issued a statement saying it will "continue to explore the full implications of this in our ecumenical relations."
No one expects a sudden mass exodus out of the Anglican Communion because of the Vatican announcement.
"We're not talking floodgates," said Paul Handley, editor of the Church Times a London-based weekly that covers Anglican affairs.
"There are a significant number of people who remain loyal Anglicans who will be seriously (tried) by this," he said, adding that they may want to remain part of the Church of England but will "feel increasingly exposed if their friends start disappearing to Rome."
Some Anglo-Catholics who have not yet left the Anglican fold could choose to stay for a variety of reasons, including a desire to avoid lengthy and expensive battles over parish property. Others may oppose the ruling that married Anglicans cannot become Catholic bishops.
The Rev. Christopher Stainbrook, pastor of St. Timothy's Episcopal Church, an Anglo-Catholic parish that is part of the Episcopal Diocese of Fort Worth, Texas, said it was far too soon to know the implications for his parish or others like it in the U.S.
Indeed, Levada made clear that the next step - publication of the pope's Apostolic Constitution outlining the new provision - would be the start of a lengthy process of consultation with Catholic bishops around the world about how to implement the change.
Still, Stainbrook and other traditionalist Anglican groups were elated by the Vatican announcement.
While some Anglicans will want to remain in the Anglican Communion, others "will begin to form a caravan, rather like the People of Israel crossing the desert in search of the Promised Land," said two traditionalist Anglican clerics in Britain, Bishop Andrew Burnham of Ebbsfleet and Bishop Keith Newton of Richborough.
The Anglican Communion has been divided for decades over interpreting the Bible on many issues, including ordaining women. But the rift blew wide open in 2003 when the Episcopal Church consecrated the first openly gay bishop, V. Gene Robinson of New Hampshire.
Williams has struggled ever since to keep the church from splitting, frustrated by moves by churches in the United States, Canada and elsewhere to bless gay relationships.
At least four conservative U.S. dioceses and dozens of individual Episcopal parishes have voted to leave the national denomination, with many affiliating themselves with like-minded Anglican leaders in Africa and elsewhere.
Associated Press writers Rachel Zoll in New York and Gregory Katz and Robert Barr in London contributed to this report.