
Hasidic Judaism or Hasidism, from the Hebrew: חסידות -Hasidus meaning "piety", is a branch of Orthodox Judaism that promotes spirituality and joy through the popularisation of Jewish mysticism as the fundamental aspects and of the Jewish faith. The majority of Hasidic Jews are ultra-orthodox. It sought to add to required standards of ritual observance, while relaxing others where inspiration predominated. Its communal gatherings celebrated soulful song and storytelling as forms of mystical devotion. This charismatic appeal has influenced wider modern Jewish denominations, while its scholarly thought has interested contemporary academic study. Each dynasty follows its own principles; thus Hasidic Judaism is not one movement, but a collection of separate individual groups with some commonality. There are approximately 30 larger Hasidic groups, and several hundred minor groups. Though there is no one version of Hasidism, individual Hasidic groups often share with each other underlying philosophy, worship practices, dress and songs.
In Poland, where the bulk of Eastern European Jewry had established itself since the 13th century, two branches of Rabbinic Judaism had emerged: those who opposed the study of Kabbalah (Jewish mysticism) and those who supported it. This schism became particularly acute after the Messianic movement of Sabbatai Zevi in the 17th century. Leanings to mystical doctrines and sectarianism showed themselves prominently among the Jews of the south-eastern provinces of Poland, while in the Lithuanian provinces, anti-kabbalist orthodox leaders held sway. In part, this division in modes of thought reflected social differences between the northern (Lithuanian) Jews and the southern Jews of Ukraine. In Lithuania the Jewish masses mainly lived in densely-populated towns where anti-kabbalistic rabbinical academic culture (in the yeshivos) flourished, while in Ukraine the Jews tended to live scattered in villages far removed from intellectual centers. In these villages, the influence of the kabbalists prevailed.
Pessimism in the south became more intense after the Cossacks' Uprising (1648–1654) under Chmielnicki and the turbulent times in Poland (1648–1660), which ruined the Jewry of Ukraine, but did not much affect that of Lithuania. The general population of Ukraine itself declined and economic chaos reigned, especially due to these events and the subsequent Turkish Invasion which left this region depopulated and barren. After the Polish magnates regained control of southern Ukraine in the last decade of the 17th century, an economic renaissance ensued. The magnates began a massive rebuilding and repopulation effort while being generally welcoming and benevolent towards the Jews. A type of frontier environment ensued where new people and new ideas were encouraged. The state of the Jews of what would later become southern Russia created a favorable field for mystical movements and religious sectarianism, which spread in the area from the middle of the 18th to the middle of the 19th century.
Besides these influences, deeply-seated causes produced among many Jews a discontent with Rabbinism and a gravitation toward mysticism. Rabbinism, which in Poland had become transformed into a system of religious formalism, no longer provided a satisfactory religious experience to many Jews. Although traditional Judaism had adopted some features of Kabbalah, it adapted them to fit its own system: it added to its own ritualism the asceticism of the "practical kabbalists" just across the border in the Ottoman Empire, who saw the essence of earthly existence only in fasting, in penance, and in spiritual sadness. Such a combination of religious practices, suitable for individuals and hermits, did not suit the bulk of the Jews.
Mystical individuals arose, outside the Rabbinic establishment, called Nistarim or Baal Shem ("Masters of the Name" of God, used for practical kabbalistic intervention and miracles), who sought to offer the downtrodden masses spiritual and physical encouragement, and practical healing. The image of these charismatic figures, often wandering among the people, became shaped by the Kabbalistic legend of the Lamed Vav Tzadikim (36 hidden righteous people who sustain the world). From these circles of spiritual inspiration, the early Hasidic movement arose, led by Israel ben Eliezer, the Baal Shem Tov, in 18th Century Podolia (now Ukraine). He attracted to his cause the preceding followers of the ways of the Nistorim, who saw in his teachings a new direction in reviving and consoling the masses.