After setting off from Rome this May on his first trip to Latin America, the world's most Roman Catholic region, Pope Benedict XVI made a top concern clear: These are "difficult times for the church," he told hundreds of bishops in Brazil, amid "aggressive proselytizing" by born-again Protestant congregations.
The times are particularly difficult in Brazil, which has seen a dramatic decline in Catholicism in urban areas, says Timothy Shah, adjunct senior fellow for religion and foreign policy at the Council on Foreign Relations in Washington.
It is also a fascinating time, he says. Brazil can now claim to be both the world's largest Catholic country and one of the largest Pentecostal nations, he notes.
But proselytism alone cannot account for one of religion's most dramatic demographic shifts: The number of Protestants increased from 6.6 percent of the Brazilian population in 1980 to 15.4 percent 20 years later.
The Pentecostal movement began here in the early 20th century, with an Italian missionary establishing the first Pentecostal church in 1910 in Sao Paulo, according to the Washington-based Pew Research Center.
Subsequent waves followed, beginning in the 1950s and '60s.
In the past two decades, Pentecostals have gone mainstream - with television stations and political candidates.
Brazil's religious landscape has since changed more than most Latin American countries.
John Burdick, an associate professor of anthropology at Syracuse University in New York, explains that non-Catholic religions tend to take root in places without a strong presence of Catholic institutions, which have had a near monopoly on Latin America since it was colonized.
Brazil has a particularly low ratio of priests to parishioners. The Getulio Vargas Foundation in Rio de Janeiro released a report upon the pope's arrival in May showing four Protestant ministers in Brazil for every Catholic priest.
In favelas, or shantytowns, throughout Rio de Janeiro, there's always a small Pentecostal church within walking distance. …