In the late Middle Ages, when Europe and western Asia were divided into Christian and Islamic countries, the Jewish people also found themselves divided into two main groups. Jews in Central and Eastern Europe, namely in Germany and Poland, were called Ashkenazi. Sephardic Jews can trace their tradition back to the Mediterranean countries, particularly Spain and Portugal under Muslim rule. When they were expelled in 1492, they settled in North Africa, the eastern Mediterranean, the Far East, and northern Europe. The two traditions differ in a number of ritual and cultural details, but their theology and basic Jewish practice are the same.
Over the past two centuries the Ashkenazi Jewish community has divided into a number of Jewish denominations; each has a different understanding of what principles of belief a Jew should hold, and how one should live as a Jew. To some degree, these doctrinal differences have created schisms between the Jewish denominations. Nonetheless, there is some level of Jewish unity. Many non-Ashkenazi Jews are members of congregations affiliated with the various movements. They describe their religious practice as "traditional" or "observant", as opposed to "Orthodox" or "Conservative".
Orthodox Judaism holds that both the Written and Oral Torah were divinely revealed to Moses, and that the laws within it are binding and unchanging. Orthodox Jews generally consider commentaries on the Shulchan Aruch such as the Moses Isserlis's HaMappah and the Mishnah Berurah, to be the definitive codification of Jewish law, and assert a continuity between the Judaism of the Temple in Jerusalem, pre-Enlightenment Rabbinic Judaism, and modern-day Orthodox Judaism.
Most of Orthodox Judaism holds to one particular form of Jewish theology, based on Maimonides' 13 principles of Jewish faith. Orthodox Judaism broadly shades into two main styles, Modern Orthodox Judaism and Haredi Judaism. The philosophical distinction is generally around accommodation to modernity and weight placed on non-Jewish disciplines. According to most Orthodox Jews, Jewish people who do not keep the laws of Shabbat and Yom Tov, kashrut, and family purity are considered non-religious.
Modern Orthodox Judaism emphasizes strict observance of religious laws and commandments but with a broad, liberal approach to modernity and living in a non-Jewish or secular environment.
Haredi Judaism, also known as "ultra-Orthodox Judaism," is a very conservative form of Judaism. The Haredi world revolves around study, prayer and meticulous religious observance. Some Haredi Jews are more open to the modern world, perhaps most notably the Lubavitch Hasidim, but their acceptance of modernity is more a tool for enhancing Jewish faith than an end in itself.
Hasidic philosophy is rooted in the Kabbalah, and Hasidic Jews accept the Kabbalah as sacred scripture. They are distinguished both by a variety of special customs and practices including reliance on a Rebbe or supreme religious leader, and a special dress code particular to each Hasidic group.
Conservative Judaism, known as Masorti Judaism outside of the United States and Canada, developed in Europe and the United States in the 1800s as Jews reacted to the changes brought about by the Enlightenment and Jewish emancipation.
