▁ ▁In ▁the ▁Lev ant , ▁the ▁inv ading ▁R ash id un ▁army ▁were ▁engaged ▁by ▁a ▁By z antine ▁army ▁composed ▁of ▁imperial ▁troops ▁as ▁well ▁as ▁local ▁lev ies . ▁According ▁to ▁Islam ic ▁histor ians , ▁Mon oph ys ites ▁and ▁Jews ▁throughout ▁Sy ria ▁wel com ed ▁the ▁Arab s ▁as ▁liber ators , ▁as ▁they ▁were ▁dis content ed ▁with ▁the ▁rule ▁of ▁the ▁By z ant ines . ▁ ▁The ▁Roman ▁Emperor ▁Her ac lius ▁had ▁fallen ▁ill ▁and ▁was ▁unable ▁to ▁personally ▁lead ▁his ▁arm ies ▁to ▁resist ▁the ▁Arab ▁con quest s ▁of ▁Sy ria ▁and ▁Roman ▁Pa el est ina ▁in ▁ 6 3 4 . ▁In ▁a ▁battle ▁fought ▁near ▁A j nad ay n ▁in ▁the ▁summer ▁of ▁ 6 3 4 , ▁the ▁R ash id un ▁C ali ph ate ▁army ▁achieved ▁a ▁decis ive ▁victory . ▁After ▁their ▁victory ▁at ▁the ▁F ahl , ▁Muslim ▁forces ▁conquer ed ▁Dam asc us ▁in ▁ 6 3 4 ▁under ▁the ▁command ▁of ▁K hal id ▁ibn ▁al - W al id . ▁The ▁By z antine ▁response ▁involved ▁the ▁collection ▁and ▁dispatch ▁of ▁the ▁maximum ▁number ▁of ▁available ▁troops ▁under ▁major ▁command ers , ▁including ▁The odore ▁Tr ith y ri us ▁and ▁the ▁Armen ian ▁general ▁V ah an , ▁to ▁e ject ▁the ▁Muslim s ▁from ▁their ▁newly ▁won ▁territ ories . ▁ ▁At ▁the ▁Battle ▁of ▁Y arm ou k ▁in ▁ 6 3 6 , ▁however