▁side ▁of ▁the ▁fort ▁were ▁open . ▁The ▁Muslim s , ▁engaged ▁closely ▁against ▁the ▁fort , ▁considered ▁themselves ▁so ▁heavily ▁committed ▁that ▁they ▁could ▁not ▁break ▁contact . ▁According ▁to ▁early ▁histor ians ▁both ▁sides ▁were ▁under ▁sie ge ! ▁The ▁operations ▁considered ▁mainly ▁of ▁arch ery ▁and ▁sal lies ▁by ▁the ▁g arrison ▁of ▁the ▁fort . ▁ ▁This ▁state ▁of ▁affairs ▁continued ▁for ▁several ▁weeks ▁until ▁both ▁sides ▁felt ▁equally ▁tired ▁and ▁equally ▁hurt ▁by ▁the ▁st alem ate . ▁Then ▁one ▁day ▁a ▁Muslim ▁officer ▁said ▁to ▁I y ad , ▁In ▁certain ▁circumstances ▁wisdom ▁is ▁better ▁than ▁a ▁large ▁army . ▁Send ▁to ▁K hal id ▁for ▁help ▁. ▁I y ad ▁agreed . ▁He ▁wrote ▁K hal id ▁ibn ▁al - W al id ▁a ▁letter ▁explaining ▁the ▁situation ▁at ▁Da um at - ul - J andal ▁and ▁seeking ▁his ▁help . ▁ ▁This ▁letter ▁reached ▁K hal id ▁as ▁he ▁was ▁about ▁to ▁leave ▁Ain - ut - T am r ▁for ▁al - H ira . ▁The ▁situation ▁on ▁the ▁Ira q ▁front ▁was ▁now ▁stable ▁and ▁he ▁had ▁able ▁lie uten ants ▁to ▁deal ▁with ▁the ▁Pers ians . ▁With ▁an ▁army ▁of ▁about ▁ 6 , 0 0 0 ▁men , ▁he ▁left ▁Ain - ut - T am r ▁the ▁following ▁day ▁to ▁join ▁I y ad . ▁The ▁movement ▁of ▁K hal id ▁was ▁discovered ▁by ▁the ▁def enders ▁of ▁Da um at - ul - J andal ▁a ▁good