A mob attack approved or condoned by authority, frequently against religious, racial, or national minorities – most often against Jews. The first occurred in the Ukraine following the assassination of Alexander II (1881). Subsequently there were many pogroms throughout Russia, causing many Russian Jews to emigrate to the USA and western Europe, often giving their support to Herzl’s Zionist campaign. After the revolution of 1905, anti-Semitic persecutions increased. Conducted on a large scale in Germany and eastern Europe after Hitler came to power they led ultimately to the Holocaust.