Political divisions intensified even further as the Eastern faction in turn split between the hard-line Northern faction (Buk-in) and the moderate Southern faction (Nam-in) and the Western factions split between the Old Doctrine(Noron) and the Young Doctrine(Soron). These factional splits grew out of allegiance to different philosophical schools and regional differences. For instance, the Eastern faction was largely Yeongnam-based, and its subfaction Southerners were mainly followers of Yi Hwang while Northerners coalesced around the school of Jo Shik. Gyeonggi and the Chungcheong-based Western faction were largely followers of Yi I, of which followers of Seong Hon split to form the Soron faction while Song Siyeol's followers became the Noron faction. These divisions were often further driven by questions concerning royal succession or appropriate royal conduct. The factions were often named after relative location of its leader's house. Easterners vs Westerners In the initial split of Sarim into the Western and Eastern factions, there was a large element of generational conflict. The Westerners were largely older Sarim scholars who entered politics during Myeongjong's reign while the Easterners, led by Kim Hyo-won (김효원) were mainly younger generation who became officials in Seonjo's reign and saw themselves uncorrupted by excesses of Myeongjong's era, which was marred by his maternal uncle Yoon Won-hyeong's corruption. The Westerners were led by Shim Eui-gyeom (심의겸), Myeongjong's brother-in-law whose house was on the west of the palace. Although Sarim scholars were usually hostile to royal in-laws as corrupting influence, Shim was Yi Hwang's disciple and protected Sarim scholars by impeaching his uncle who was planning another literati purge. In addition, many Westerners were disciples of Yi I and Seong Hon and followers of Giho school while many Easterners were disciples of Yi Hwang and Jo Shik and followers of Youngnam School. Easterners emphasized moral purification of the ruling class and rooting out corruption of earlier period while Westerners emphasized reforms that would strengthen the country and improve livelihood. (Easterners blamed Shim Eui-gyeom's ill-willed opposition to Kim Hyo-won's appointment at a key position in Ministry of Personnel for split while Westerners blamed Easterner's self-righteous attack.) Yi I attempted to prevent the factional split by appointing Shim Eui-gyeom and Kim Hyo-won to provincial posts far away from the court and arranging truce between Easterner Yi Bal and Westerner Jeong Cheol. After Yi I's death, however, the conflict between two factions became more intense as the Easterners impeached Shim Eui-gyeom and