Jeong Cheol, leading to their dismissal, and gained upper hand. In 1589, Easterner Jeong Yeo-rip was accused of treason because he formed a society with his supporters that met each month to study and receive military training. History of the Sarim after its split is very complicated because there is a wealth of conflicting historical accounts written by each faction. This is especially true with what became known as Gichuk Treason Case of 1589 (기축옥사), the bloodiest purge in Joseon history by far. There is still a dispute about the nature and purpose of Jeong Yeo-rip's group of armed supporters and whether it was treason or frame up. His group was not a secret society as it helped the local government to help fight against the Japanese marauders. On the other hand, it appears that Jeong truly had revolutionary ideas that was close to republicanism. He believed that the world was something to be shared and therefore there could not be one master. His group, called "Great Common Society"(대동계), could be joined by anyone regardless of one's social status, and it spread throughout Honam province and to other regions as well. In any case, Jeong Yeo-rip committed suicide after his arrest was ordered, which was considered the admission of guilt, and letters of Easterners were discovered from his house. Jeong Cheol, famous poet and head of the Western faction, was in charge of investigating the case and used the case to effect widespread purge of Easterners who had slightest connection with Jeong Yeo-rip. According to Easterners' accounts, Jeong Cheol tortured even 80-year-old mother and 8-year-old son of Yi Bal, leader of Eastern faction. According to Westerners' accounts, Jeong Cheol tried heroically to save Yi Bal and Choe Yeong-gyeong from Seonjo's wrath. In any event, 1,000 Easterners were killed or exiled in the aftermath. It is also believed that Seonjo used this incident to weaken the Sarim's power. Northerners vs. Southerners This incident put the Westerners in power, but did not last long because of intrigue involving the appointment of the crown prince, which put the Easterners back in power for thirty years. The Eastern faction soon split into hardline Northern faction (Buk-in), which wanted to put Jeong Cheol and other Westerners to death, and moderate Southern faction (Nam-in), which did not want a wholesale purge. The Northerners were largely disciples of Jo Shik and Seo Gyeong-deok and suffered more from