Academic study of Jewish mysticism, especially since Gershom Scholem's Major Trends in Jewish Mysticism (1941), distinguishes between different forms of mysticism across different eras of Jewish history. Of these, Kabbalah, which emerged in 12th-century Europe, is the most well known, but not the only typologic form, or the earliest to emerge. Among previous forms were Merkabah mysticism (c. 100 BCE – 1000 CE), and Chassidei Ashkenaz (early 13th century CE) around the time of Kabbalistic emergence.