uals ▁and ▁this ▁was ▁now ▁being ▁strictly ▁applied ▁by ▁the ▁Portuguese ▁Francis can ▁bishop ▁of ▁Be ij ing ▁Alexandre ▁de ▁G ouve a . ▁When ▁his ▁mother ▁died ▁in ▁ 1 7 9 1 , ▁Y un ▁therefore ▁refused ▁to ▁perform ▁the ▁usual ▁Conf u cian ▁cer emon ies ; ▁this ▁became ▁public ▁knowledge , ▁he ▁was ▁accused ▁of ▁im pi ety ▁and ▁was ▁executed . ▁Some ▁Kore ans ▁who ▁had ▁at ▁first ▁been ▁sympath etic , ▁hor r ified ▁by ▁the ▁Church ' s ▁re jection ▁of ▁h allowed ▁trad itions , ▁turned ▁away . ▁Je ong ▁Y ak y ong ▁may ▁well ▁have ▁been ▁among ▁them . ▁ ▁Royal ▁Service ▁Das an ▁was ▁particularly ▁interested ▁in ▁civil ▁engineering ▁and ▁in ▁ 1 7 9 2 ▁the ▁king , ▁im pressed ▁by ▁a ▁p onto on ▁bridge ▁he ▁had ▁designed , ▁asked ▁him ▁to ▁design ▁and ▁super v ise ▁the ▁construction ▁of ▁the ▁walls ▁for ▁the ▁H w ase ong ▁Fort ress ▁( mod ern ▁Su won ), ▁which ▁surrounded ▁the ▁palace ▁where ▁the ▁king ▁would ▁live ▁when ▁he ▁visited ▁the ▁new ▁tomb ▁he ▁had ▁constructed ▁for ▁his ▁father . ▁Das an ▁produced ▁rad ically ▁new ▁techniques ▁and ▁structures , ▁drawing ▁on ▁European , ▁Chinese ▁and ▁Japanese ▁sources . ▁In ▁ 1 7 9 4 , ▁after ▁several ▁prom ot ions , ▁the ▁king ▁appointed ▁him ▁as ▁secret ▁en voy ▁to ▁G ye ong i ▁province , ▁investig ating ▁reports ▁of ▁cor ruption . ▁ ▁Das an ' s ▁most ▁important ▁task