Many premodern Chinese intellectual traditions and 'schools' (especially philosophical and religious ones) share the common characteristic of being retrospectively created. New Confucianism provides students of Chinese intellectual history with a rare opportunity to study this traditional strategy of orthodoxy formation in a contemporary context. One of the earliest and most influential examples of the practice is Sima Tan's 司馬談 (ca. 180–110 b.c.) essay on the essential characteristics of the six 'schools' (jia 家) of pre-Qin thought, in which four of the 'schools' he identifies—the Legalists, the School of Names, the Daoists, and the Cosmologists—are retrospectively created. Sima Tan's taxonomy has exercised a lasting influence on the historiography of classical Chinese thought. Even today, standard textbooks still largely adhere to his classifications. The authority of his taxonomy was consolidated when it was subsequently adopted by bibliographers, Liu Xiang 劉向 (79–8 b.c.), in his Bielu 別錄, and his son, Liu Xin 劉歆 (46 b.c. to a.d. 23), in his Qilüe 七略. The Lius contributed to the genealogical dimension of the classifications by identifying and assigning individual writers to particular categories.