irth ▁and ▁child hood ▁▁ ▁John ▁was ▁born ▁in ▁Dam iet ta , ▁Egypt . ▁He ▁was ▁the ▁sixth ▁child ▁and ▁the ▁fourth ▁son ▁of ▁king ▁Louis ▁IX ▁of ▁France , ▁called ▁St . ▁Louis ▁after ▁canon ization , ▁and ▁Margaret ▁of ▁Prov ence . ▁Moreover , ▁he ▁was ▁the ▁first ▁of ▁three ▁children ▁of ▁this ▁royal ▁couple ▁who ▁were ▁born ▁during ▁the ▁Se vent h ▁Cr us ade . ▁He ▁was ▁born ▁at ▁the ▁Egypt ian ▁port ▁town ▁of ▁Dam iet ta ▁which ▁had ▁been ▁conquer ed ▁by ▁the ▁cr us aders ▁in ▁ 1 2 4 9 . ▁According ▁to ▁chron ic ler ▁Jean ▁de ▁Jo in ville , ▁an ▁old ▁kn ight ▁acted ▁as ▁mid w ife ▁during ▁John ' s ▁birth . ▁Two ▁days ▁prior ▁to ▁his ▁birth , ▁the ▁king ▁was ▁captured ▁by ▁the ▁Mam lu ks ▁which ▁was ▁the ▁reason ▁to ▁name ▁the ▁child ▁Tr istan ▁due ▁to ▁the ▁tr iste ▁occasion . ▁He ▁was ▁bapt ised ▁in ▁the ▁grand ▁mos que ▁of ▁Dam iet ta ▁that ▁had ▁been ▁re - con sec r ated ▁into ▁a ▁church . ▁One ▁month ▁later , ▁Dam iet ta ▁had ▁to ▁be ▁abandoned . ▁John ▁subsequently ▁spent ▁his ▁child hood ▁in ▁the ▁Holy ▁Land ▁where ▁his ▁sib lings ▁Peter ▁( 1 2 5 1 ) ▁and ▁Bl anche ▁( 1 2 5 3 ) ▁were ▁born . ▁ ▁Mar riage ▁▁ ▁His ▁father ▁wished ▁that ▁John ▁joined ▁the ▁Domin ican ▁Order , ▁but ▁John ▁resist ed ▁this ▁wish ▁successfully .