Gihae Persecution
Under Heonjong the Pungyang Jo regime executed three French priests who had entered secretly, along with many Korean Catholics, and issued a royal edict condemning Catholicism.

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Bishop Imbert and Fathers Maubant and Chastan were executed at Saenamteo, and many believers including Jeong Ha-sang died; Jeong left a written defence of the faith addressed to the chief minister.
The persecutions ran 1791 (Sinhae) → 1801 (Sinyu) → 1839 (Gihae) → 1846 (Byeongo, martyrdom of Father Andrew Kim Dae-geon) → 1866 (Byeongin), the last becoming the pretext for the French expedition of 1866.