The persecution of Christians can be historically traced from the first century of the Christian era to the present day. Early Christians were persecuted for their faith at the hands of both the Jews from whose religion Christianity arose and the Romans who controlled many of the lands across which early Christianity was spread. Early in the fourth century, a form of the religion was legalized by the Edict of Milan, and it eventually became the State church of the Roman Empire. Christian missionaries and converts to Christianity have both been targets of persecution, sometimes to the point of being martyred for their faith, ever since the emergence of Christianity. The schisms of the Middle Ages and the later Protestant Reformation, sometimes provoked severe conflicts between Christian denominations and during these conflicts, members of these different denominations frequently and violently persecuted each other. In the 20th century, Christians were persecuted, sometimes to the point of genocide, by various governments, including the government of the Ottoman Empire, which committed the Armenian Genocide and the governments of atheistic states such as the Soviet Union, Communist Albania and North Korea.
Numerosos cristianos han sufrido persecuciones por parte de no cristianos e incluso de otros cristianos de creencias diversas o más o menos estrictas durante la historia del cristianismo. Tales persecuciones tienen o tuvieron varios grados de intensidad, desde el arresto sin garantías, la mengua de derechos públicos, el encarcelamiento, el azotamiento y la tortura, hasta la ejecución, llamada martirio, pasando por el pago de un impuesto suplementario —como el caso de los mozárabes—, la confiscación de sus bienes o incluso la destrucción de sus propiedades, su arte, sus libros y sus símbolos o la incitación a abjurar de sus principios y delatar a otros cristianos.