The Montanists were members of a Christian movement that emerged in the late 2nd century, founded by a man named Montanus in Phrygia, a region in modern-day Turkey. They emphasized the role of the Holy Spirit and believed in ongoing revelation, claiming that new prophecies were being given to them. This led to a focus on spiritual experiences and a more rigorous moral code. Montanism attracted followers who sought a deeper spiritual life, but it faced criticism from mainstream Christian leaders. They viewed Montanism as a challenge to established church authority and doctrine, leading to its eventual decline by the 4th century.