Steenson stepped down in 2007 as the Episcopal bishop of Rio Grande, in Albuquerque, N.M., after the Episcopal Church elected its first openly gay bishop, V. Gene Robinson of New Hampshire. Steenson had said he was "deeply troubled" about the direction of the U.S. denomination, and he described the Catholic Church as the "true home of Anglicanism."
The Episcopal Church is the U.S. Anglican body in the United States.
Benedict in 2009 issued an unprecedented invitation for Anglicans to become Catholic in groups or as parishes, at a time when traditional Anglicans in several countries were increasingly upset by the ordination of women and gay bishops. Formerly, Anglican converts to Catholicism were accepted case by case.
The pope's decision created tensions with Archbishop of Canterbury Rowan Williams, the spiritual leader of the world Anglican Communion, who, like his predecessors, had been in talks with Vatican officials to bring Anglicans and Catholics closer together.
The Anglican fellowship, with 77 million members, has its roots in the Church of England, which split from the Holy See in 1534 when English King Henry VIII was refused a marriage annulment.
At the time of the pope's announcement, Anglicans were already fracturing over Robinson's election and other issues. Williams had little notice of the Vatican announcement. Still, after meeting privately with the pope soon after, he said he was convinced that there was no "dawn raid" on his church by the Holy See.
Under the pope's plan, Anglicans who become Catholic will be allowed to keep some of their heritage in liturgy and other areas. Married Anglican priests who convert can stay married and be ordained in the Catholic Church, an exception to the Vatican's celibacy rule. Married Anglican bishops, however, cannot retain that position and will serve the Catholic Church as priests.
More than 100 Anglican clergy have applied to become Catholic priests in the U.S. ordinariate. Church officials said more than 1,400 individuals were seeking to join. The U.S. Episcopal Church has just under two million members. Many Anglo-Catholics in the United States had never been part of the Episcopal Church.
Steenson, 59, has a doctorate from the University of Oxford. He has been married since 1974 and has three adult children. His wife also converted to Catholicism.