Orthodox Judaism claims to be the faithful heir to classical, or normative, rabbinic Judaism. However, as a distinct denomination of modern Judaism, Orthodoxy was established in mid-19th-century central Europe in reaction to the radical changes to tradition introduced by Reform Judaism.
The rapid spread of the haskalah, or Jewish enlightenment in western Europe, followed by the Reform movement's widespread successes, generated the deeply conservative and separationist ideology that came to characterize Orthodox Judaism. Among the most significant rabbinical influences on the founders of the Orthodoxy were R. Elijah (the Gaon) of Vilna and R. Ezekiel Landau of Prague.
Although Orthodoxy claims no official founders, as it considers itself the authentic version of ancient Judaism and not a product of the modern era, two 19th-century rabbis—Samson Raphael Hirsch in Germany and Moses Sofer in Hungary—are widely considered to be the ideological forefathers of Orthodox Judaism.
Aside from the Torah, whose full and exact text is believed by Orthodox Jews to have been revealed directly to Moses by God and transmitted intact through the generations, Orthodoxy has a large body of authoritative rabbinical texts—most importantly the Talmud and the 16th-century legal code, Shulchan Aruch.
Despite Orthodoxy's belief that it represents the unchanged will of God as interpreted over the millennia by rabbis representing an "unbroken chain of tradition," the term "Orthodox" first came into use in the 19th century. Orthodoxy has evolved in reaction to a wide range of challenges and changing conditions in the modern world.