Anti-Jewish pogroms in the Russian Empire
The term "pogrom" in the meaning of large-scale, targeted, and repeated anti-Jewish rioting, saw its first use in the 19th century, in reference to the anti-Jewish pogroms in the Russian Empire. Pogroms began occurring after the Russian Empire, which previously had very few Jews, acquired territories with large Jewish populations during 1791-1835. These territories were designated "the Pale of Settlement" by the Russian government, within which Jews were reluctantly permitted to live, and it was within them that the pogroms largely took place. Most Jews were forbidden from moving to other parts of the Empire, unless they converted to Orthodox Christianity.
Odessa, 1821
The first pogrom is sometimes considered to be the 1821 Odessa pogroms (in modern Ukraine) after the execution of the Greek Orthodox patriarch Gregory V in Constantinople, in which 14 Jews were killed. The initiators of the 1821 pogroms were the local Greeks, who used to have a substantial diaspora in the port cities of what was known as Novorossiya. Some sources consider the first pogrom to be the 1859 riots in Odessa.