Christianity is the most widespread religion on Earth today, with nearly one third of all human beings subscribing to one of its thousands of denominations. Many of christian concepts are well-known and recognized globally, but there is one concept that strongly influenced a tremendous number of people that do not follow this religion. It is the concept of antisemitism, the idea that people of the jewish ethnicity must be put to death (or otherwise punished) because of the New Testament account of the execution of Jesus Christ for the charge of blasphemy under Jewish law. In less extreme forms, the notion of antisemitism has entered the popular culture of christians and non-christians alike, and the jewish diaspora became the target of baseless non-religious accusations of many kinds, from poisoning the wells to new world order conspiracies.
Although jews were blamed for deicide in the Christian bible and in the writings of the Church Fathers and early Popes, none of them called for physical violence or murder, staying somewhat true to their Christian concept of forgiveness. Augustine of Hippo, for example, wrote that the Jews should be left alive and suffering as a perpetual reminder of their murder of Christ. This did not hold true to the masses of the Christian followers, many of who ignored the Popes and the christian leaders speaking of peace, and fostered hatred
The large scale prosecution of the jews by the christians began in the 12th century. Although significant conflicts have happened much earlier as well, such as when thousands of Christians were slaughtered by the combined forces of Persians and Jews retaking Jerusalem in 617 CE, those were part of regular warfare. The first truly organized outbreak of violence against Jews happened during the First Crusade, in what the historians call the First Holocaust, when, in 1096, the german army massacred the jews of the Rhine Valley. Although preaching against the “Enemies of Christ” was directed at the Muslims, Jews were much easier to find. The catholic church at the time was protecting the jews from these purges, and Pope Calixtus II issued a bull in 1120, forbidding the christians to harm them or take their property, which was reaffirmed by many Popes thereafter, but antisemitism was no longer under control of the church.
Everywhere across Europe came religious accusations of Blood Libel (drinking of the blood of christian children, the first in 1144 leading to the massacres of the jews in Norwich, England, the last one causing deaths of the accused jews perhaps 1529 in Bösing, Hungary) and Host desecration (mistreatment of a Catholic communion wafer, over 100 instances of executions by burning to death, from 1243 in Berliz, Germany to 1761 in Nancy, France), or even well poisoning (which proliferated during the time of the Black Death in mid 14th century). These were followed by burning the accused jews to death, massacres, pogroms, purges, and even full scale expulsions from England (1290), France (many times from 1182 to 1396), Austria (1421), Spain (1492) and Portugal (1496), and from select cities and municipalities all the way until the 20th century. The Catholic Inquisition relentlessly tortured and executed even the jews that converted to Christianity, particularly fierce in 16th century Spain and 17th century Portugal and Portugal-occupied India. Antisemitism remained widespread in the 18th and 19th centuries throughout Europe and worst of all, Czarist Russia. Notably, in France, where the Jews were fully integrated into the society by law since 1789, nationalistic Catholic forces launched Dreyfus Affair, a major political attack on the French jews, which the catholics lost, leading to the loss of the privileged status of Roman Catholic Church in France in 1905 and, simultaneously, to the start of the Zionist movement which ultimately created state of Israel in the 20th century.
Finally, as we all know, antisemitism came to its peak during World War II, when the ideology of Nazism made strong religious and racial antisemitism one of its main aspects. Building in part on the 16th century words of Martin Luther, who demanded that the Jews’ homes be destroyed, their synagogues burned, money confiscated, and on the late 19th century Aryan Christianity, the Nazis not only accused the Jews of deicide, demanding their complete expulsion from all things Christian, including the Bible itself, but listed the Jews alongside other soulless subhuman races, devoid of divine protection, stripping them of any rights and ordering their total extermination.
When the horrors of the german extermination camps were exposed, the public opinion of the christian nations, for the first time in over a thousand years, became critical of antisemitism and supportive of the jews, although antisemitism is still the norm in much of the Islamic world and still maintains its pervasive presence in the western society.