Anti-Catholicism is a generic term for discrimination, hostility or prejudice directed against Catholicism, and especially against the Catholic Church, its clergy or its adherents. The term also applies to the religious persecution of Catholics or to a "religious orientation opposed to Catholicism."
In the Early Modern period, the Catholic Church struggled to maintain its traditional religious and political role in the face of rising secular powers in Europe. As a result of these struggles, there arose a hostile attitude towards the considerable political, social, spiritual and religious power of the Pope of the day and the clergy in the form of "anti-clericalism". To this was added the epochal crisis over the church's spiritual authority brought about by the Protestant Reformation, giving rise to sectarian conflict and a new wave of anti-Catholicism.
In more recent times, anti-Catholicism has assumed various forms, including the persecution of Catholics as members of a religious minority in some localities, assaults by governments upon them, discrimination, desecration of churches and shrines, and virulent attacks on clergy and laity.
Read more about Anti-Catholicism: Persecution of Early Christians in The Roman Empire, In Protestant Countries, In Catholic Countries, Orthodox Christianity, Sri Lanka, In Apologetics, In Popular Culture