Zhāng Bóduān 張伯端 (c. 987–1082), zì Píng shū 平叔, styled Zǐ yáng zhēn rén 紫陽真人, of Tiān tái 天台 (Zhè jiāng). The founding patriarch of the Southern Lineage (Nán zōng 南宗) of nèi dān — author of the Wù zhēn piān 悟真篇 (1075), the second cornerstone of Chinese inner-alchemy after the Cān tóng qì. Also attributed KR5d0104 Jīn dān sì bǎi zì 金丹四百字 (“Four Hundred Characters on the Gold Elixir”). His synthesis of the Cān tóng qì alchemical framework with nèi dān physiological practice was the decisive shaping influence on all subsequent Southern-Lineage (Chén Nán, Bái Yùchán) and Yuán-era synthesizing (Chén Zhìxū) nèi dān traditions. (Catalog meta for KR5d0104 has “張伯瑞” — a common graphical variant for the correct 張伯端.)