Yáng Guāngxiān 楊光先 (zì Chánggōng 長公; 1597–1669; native of Shèxiàn 歙縣 in Huīzhōu / Anhui) was an early-Qīng court official, military officer and ideological reactionary whose 1664 indictment of the Jesuit director of the Imperial Astronomical Bureau, 湯若望 Adam Schall, precipitated the 1664–65 Lìyù 曆獄 (“Calendar Case”) — the great anti-Jesuit persecution that nearly extinguished the Catholic mission in China and ended in Schall’s death under house arrest, the public flogging of 南懷仁 Verbiest, and Yáng’s own brief installation as Bureau Director (1665–69). His position was reversed in 1669 when the young Kāngxī emperor personally re-examined the astronomical evidence (a famous “scientific trial” in which Verbiest demonstrated the superior accuracy of the Tychonic system by public eclipse prediction), restored the Jesuits and exiled Yáng. The intellectual record of Yáng’s campaign is preserved in his Bùdé yǐ 不得已 (“I Could Do No Other”) (KR3fa028), an emphatically polemical work whose title quotes Mèngzǐ: “Yú qǐ hào biàn zāi? Yú bùdé yǐ yě” 予豈好辯哉?予不得已也 (“Am I fond of debate? I cannot help it.“) CBDB id 65958, 1597–1669.