When did Orthodox Judaism begin?

Answer 1

It depends how the question is read.

If the question is asking when Judaism began in its most traditional form, there are a variety of different opinions which posit the beginning of Judaism anywhere from 2000 BCE to 550 BCE. The typical religious Jewish opinion moves closer to the 1800 BCE mark with the life of Abraham, who Jews believe to be the first Jew. This development of Judaism would have taken place in Biblical Israel. However, Judaism requires the Divine Law to function as an orthopractical religion. Religious individuals date Moses to some time around 1300 BCE and say that God revealed to Moses both the Written Law (Torah) and the Oral Law (Mishnah, Talmud, etc.). This version of Judaism would see Judaism revealed in the Sinai Peninsula in Egypt. Western Scholars assert that Judaism came out of the JEPD theory of the Torah construction which was finalized in 550 BCE in Babylon, a city in modern Iraq.

If the question is asking specifically about the Modern Orthodox Movement in Judaism, most Orthodox Jews will say that they only acquired this name because of the prevalence of non-Orthodox forms of Judaism in Europe, specifically Germany. The Orthodox Movement was identified with Rabbi Samson Raphael Hirsch and Rabbi Azriel Hildescheimer in the mid 1800s. Because of the prevalence of Reform and Conservative Judaism in Germany, Jews who were still completely faithful to the older traditions needed to identify themselves. However, no Orthodox Jew claims that Orthodox Judaism as a belief system begin in the 1800s.