The period between 1900 and the 1960s was a time of great change and growth for Christianity. In the early 20th century, the modernist-fundamentalist controversy divided many Protestant denominations, with some embracing a more liberal, modernist theology while others clung to a more conservative, fundamentalist theology. This period also saw the rise of Pentecostalism, a revivalist movement that emphasized the experience of the Holy Spirit and miraculous gifts of the Spirit. In the Catholic Church, the early 20th century saw the growth of the charismatic movement and the widespread use of the mass media for evangelism and catechesis.
During the mid-20th century, Christianity faced new challenges and opportunities in response to the changes brought about by World War II and the rise of secularism. Many Christians responded by embracing new forms of evangelism and mission, including the youth and campus movements and the use of radio, television, and other media. In the Catholic Church, the Second Vatican Council (1962-1965) was a major turning point, as the Church embraced a new vision of its role in the world and the importance of engaging with contemporary culture. In this period, Christianity also faced significant challenges, including the rise of secularism, the civil rights movement, and the increasing influence of scientific and philosophical theories that seemed to undermine traditional Christian beliefs. Despite these challenges, Christianity continued to grow and thrive, and many new movements and denominations emerged that sought to engage the culture and bring the gospel to the world.