The Catholic Persecution of 1801, also known as the Sinyu Persecution (신유박해, 辛酉迫害), was a mass persecution of Korean Catholics ordered by regent Dowager Queen Jeongsun during King Sunjo of Joseon's reign on April 8, 1801 (the 26th of the 2nd lunar month).
Events leading up to the execution include the "Hwang Sa-yeong Incident". Church leader Hwang Sa-yeong wrote a letter that was both critical of the Joseon government and also advocated a plan to ask for a Western ship to come to Korea in an effort to aid the persecuted Catholics. The letter was intercepted on its way to Beijing. This enraged the reclusive government and Hwang was later executed.
Not all Catholics were executed, however. Some 199 were exiled and were both ridiculed and watched closely for the remainder of their lives.