Haredi Judaism
Haredi Judaism is not an institutionally cohesive or homogeneous group, but comprises a diversity of spiritual and cultural orientations, generally divided into a broad range of Hasidic sects, Litvishe-Yeshivish streams from Eastern Europe, and Oriental Sephardic Haredim. These groups often differ significantly from one another in their specific ideologies and lifestyles, as well as the degree of stringency in religious practice, rigidity of religious philosophy, and isolation from the general culture that they maintain.
Hasidic Judaism
Outside pressure was mounting in the early 20th century. In 1912, many Hasidic leaders partook in the creation of the Agudas Israel party, a political instrument intended to safeguard what was now named Orthodox Judaism even in the relatively traditional East; the more hard-line dynasties, mainly Galician and Hungarian, opposed the Aguda as too lenient. Mass immigration to America, urbanization, World War I and the subsequent Russian Civil War uprooted the "shtetl"s in which the local Jews lived for centuries and were the bedrock of Hasidism. In the new Soviet Union, civil equality first achieved and a harsh repression of religion caused a rapid secularization. Few remaining Hasidim, especially of Chabad, continued to practice underground for decades. In the new states of the Interbellum era, the process was only somewhat slower. On the eve of World War II, strictly observant Jews were estimated to constitute no more than a third of the total Jewish population in Poland, the world's most Orthodox country. While the Rebbes still had a vast base of support, it was aging and declining.