 As far as we know, Neidan developed from the early 8th century onwards. Two of its main branches, which emerged between the 12th and the 13th centuries, are traditionally ascribed with the creation of models of self-cultivation based on the concepts summarized above (Yokote 2015). The first model, associated with the Nanzong (Southern Lineage), gives initial priority to the cultivation of one’s ming (existence), gradually shifting to the cultivation of xing (inner nature) as the practice progresses. The second model, associated with the Beizong (Northern Lineage), emphasizes instead the cultivation of one’s xing by means of “clarity and quiescence” (qingjing); this is also said to involve the cultivation of one’s ming. Despite the differences between these two models, Neidan as a whole insists that both xing and ming should be cultivated, a view reflected in the term “conjoined cultivation of nature and existence” (xingming shuangxiu).