Pentecostalism hails originally from American Holiness circles at the turn of the century where desire for the spiritual gifts described in the Acts of the Apostles and Paul's epistles led to mass revivals in Topeka, Kansas, and Los Angeles, out of which, eventually, the Pentecostal denominations formed. Drawing on a theological framework indebted to John Wesley, the late 18th century founder of Methodism, classical Pentecostals believe that “baptism in the Holy Spirit,” “speaking in tongues,” healing, and other manifestations of the Holy Spirit recorded in the New Testament ought to be normative in the life of Christians today.

Traditionally, classical Pentecostal Churches have been deeply hostile to Catholicism, reviving much of the Reformation “!@#$% of Babylon” invective discarded by most modern mainstream Protestants. They have, along with conservative evangelicals, also proselytized aggressively in nominally Catholic cultures and communities. One researcher recently estimated that 30% of today's conservative Protestants in the United States are first- or second-generation former Catholics.

Modest signs of détente between some streams of Pentecostalism and the Catholic Church began to appear as early as the mid-1960s. David DuPlessis, a South African, was the lone Pentecostal observer at Vatican II, and a pioneer in bridging the vast gulf between classical Pentecostals and the wider Christian world.

And the emergence of charismatic renewals within the mainstream Churches in the same period, often inspired by the example of Pentecostals, overturned long-standing stereotypes and began to create formal ongoing contacts with Catholics, mainline Protestant Churches, and Eastern Orthodox.

—Gabriel Meyer