The queen's brother, who opposed Kim Hyo-won and led the Westerners
Although a royal in-law, he had protected the sarim and was backed by its older members. In 1575 his attempt to block Kim Hyo-won from the post of personnel section chief (Ijo jeongnang) escalated into a dispute that split the sarim into Easterners and Westerners. Because his house lay in Jeongdong in the west of the capital, his followers were called the Westerners.
A clash between Kim Hyo-won and Sim Ui-gyeom over a key personnel post split the Sarim into Easterners and Westerners, beginning factional politics.
Clashed with Sim Ui-gyeom over a key personnel post and became leader of the Easterners
Neo-Confucian scholar of western Gyeongsang who stressed reverence, righteousness and practice; his disciples formed the Northerners and led militias in the Imjin War
From the literati purges to in-law government — how Sarim factions moved from coexistence and checks to purges and one-faction rule, then through Tangpyeong to the dominance of a few clans