Lǐ Lóngjī 李隆基 (685–762), posthumously titled Emperor Xuánzōng 玄宗 (also commonly Míngdì 明皇 or Míng huángdì 明皇帝), was the sixth emperor of the Táng, reigning from 712 to 756. Grandson of Emperor Gāozōng 高宗 and Wǔ Zétiān 武則天, third son of Emperor Ruìzōng 睿宗. His reign is conventionally divided into the prosperous Kāiyuán 開元 era (713–741), in which he supervised major institutional, calendrical, and editorial projects, and the troubled Tiānbǎo 天寶 era (742–756) culminating in the An Lùshān 安祿山 rebellion of 755 and his abdication in favour of his son Sùzōng 肅宗. He is the only Táng emperor known to have personally composed two commentaries on a Confucian classic — the Xiàojīng 孝經 in 722 (revised 743), which became the canonical recension (see KR1f0002 and KR1f0004) — and to have annotated the Dàodé jīng 道德經 (732). He also patronized the compilation of the Tángliù diǎn 唐六典 and the Kāiyuán lǐ 開元禮. His autograph calligraphy survives on the Shítái Xiàojīng 石臺孝經 stele in the Xī’ān Forest of Stelae. The catalog meta yaml gives his dates as 597–649, but those are in fact the lifedates of his great-great-grandfather Emperor Tàizōng 太宗 (Lǐ Shìmín 李世民); the correct figures (685–762, CBDB id 19244) are followed here.