ine ▁to ▁be ▁an nex ed ▁by ▁the ▁R ash id un ▁C ali ph ate ▁following ▁the ▁con quest ▁of ▁Gaz a ▁by ▁Am r ▁ibn ▁al - ' As ▁in ▁ 6 3 4 . ▁Through out ▁early ▁Muslim ▁Arab ▁rule ▁and ▁until ▁the ▁arrival ▁of ▁the ▁Cr us aders ▁in ▁the ▁late ▁ 1 1 th ▁century , ▁" D ar um " ▁normally ▁referred ▁to ▁the ▁southern ▁district ▁of ▁J und ▁Fil ast in ▁whose ▁capital ▁fl uct u ated ▁between ▁the ▁towns ▁of ▁Bay t ▁J ibr in ▁or ▁Heb ron . ▁ ▁The ▁F at im id ▁cal i ph ▁al - Az iz ▁B illa h ▁( r . ▁ 9 7 5 - 9 9 6 ) ▁granted ▁his ▁fav ored ▁viz ier , ▁Y aqu b ▁ibn ▁Kill is , ▁a ▁f ief ▁in ▁modern - day ▁De ir ▁al - Bal ah , ▁as ▁test ified ▁by ▁an ▁ins cription ▁d ating ▁to ▁the ▁ 9 8 0 s ▁located ▁in ▁the ▁city ' s ▁al - K h id r ▁Mos que . ▁The ▁f ief ▁included ▁a ▁large ▁estate ▁with ▁date ▁pal ms . ▁ ▁Cr us ader ▁and ▁A yy ub id ▁rule ▁De ir ▁al - Bal ah ▁was ▁built ▁on ▁the ▁ru ins ▁of ▁the ▁Cr us ader ▁fort ▁of ▁Dar om ▁( also ▁referred ▁to ▁as ▁" D or on ") ▁which ▁was ▁built ▁by ▁King ▁Am al ric ▁I . ▁The ▁exact ▁date ▁of ▁the ▁fort