The Gabsul Hwanguk (Korean: 갑술환국) occurred in 1694. The Southerners attempt to purge Westerners on charge of plotting to reinstate deposed Queen Inhyeon backfired. The Southerners would never recover from this purge politically. However, the Westerners already split into Noron and Soron.
References
Gapsul Hwanguk Wikipedia(Text) CC BY-SA