▁form ulated . ▁This ▁was ▁the ▁start ▁of ▁an ▁increasing ly ▁close ▁relationship ▁between ▁the ▁king ▁and ▁Das an . ▁After ▁the ▁promotion ▁of ▁Ch ae ▁Je - g ong ▁in ▁ 1 7 8 8 , ▁Das an ▁took ▁top ▁place ▁in ▁the ▁da eg wa ▁( high er ▁civil ▁service ▁exam ) ▁in ▁ 1 7 8 9 ▁and ▁was ▁offered ▁a ▁position ▁in ▁the ▁Office ▁of ▁Royal ▁Dec rees , ▁together ▁with ▁ 5 ▁other ▁members ▁of ▁the ▁Sou ther ner ▁fa ction . ▁This ▁al ar med ▁members ▁of ▁the ▁oppos ing ▁‘ Old ▁Do ctrine ’ ▁fa ction , ▁who ▁soon ▁realized ▁the ▁extent ▁to ▁which ▁the ▁Southern ers ▁were ▁being ▁influenced , ▁not ▁only ▁by ▁the ▁Pract ical ▁Learning ▁introduced ▁to ▁China ▁from ▁Europe , ▁but ▁by ▁Roman ▁Catholic ism ▁itself . ▁ ▁In ▁ 1 7 8 4 , ▁Y i ▁By e ok ▁( 李 <0xE8> <0x98> <0x97> , ▁ 1 7 5 4 – 1 7 8 6 ), ▁a ▁scholar ▁who ▁had ▁participated ▁in ▁meet ings ▁to ▁study ▁books ▁about ▁the ▁Western ▁( Europe an ) ▁Learning , ▁starting ▁in ▁ 1 7 7 7 , ▁talked ▁with ▁Das an ▁about ▁the ▁new ▁religion ▁for ▁the ▁first ▁time ▁in ▁ 1 7 8 4 ▁and ▁gave ▁him ▁a ▁book ▁about ▁it . ▁Wh atever ▁his ▁own ▁response ▁may ▁have ▁been , ▁and ▁there ▁is ▁no ▁proof ▁that ▁he ▁ever ▁received ▁bapt ism , ▁Das an ' s ▁immediate ▁family ▁was ▁deeply ▁involved ▁in