rey ▁inv aded ▁Norm andy ▁on ▁a ▁campaign ▁that ▁was ▁aim ed ▁at ▁Bay e ux ▁and ▁Ca en . ▁The ▁size ▁of ▁their ▁army ▁and ▁its ▁composition ▁are ▁unknown . ▁They ▁first ▁arrived ▁in ▁the ▁H iem ois ▁region ▁of ▁Norm andy ▁and ▁began ▁ra iding ▁and ▁pill aging ▁towards ▁the ▁two ▁towns . ▁Duke ▁William , ▁who ▁appears ▁to ▁have ▁been ▁rel uct ant ▁to ▁opp ose ▁his ▁over l ord ▁directly , ▁gathered ▁a ▁large ▁army ▁at ▁F ala ise ▁but ▁took ▁no ▁other ▁action ▁besides ▁keeping ▁sc outs ▁out ▁to ▁report ▁the ▁inv ading ▁force ' s ▁movements . ▁When ▁the ▁inv aders ▁reached ▁a ▁ford ▁on ▁the ▁est u ary ▁of ▁the ▁D ives ▁River ▁near ▁Var av ille , ▁they ▁began ▁to ▁cross ▁but ▁when ▁the ▁t ide ▁came ▁in , ▁the ▁process ▁had ▁only ▁been ▁half ▁completed , ▁leaving ▁the ▁army ▁split ▁in ▁two . ▁William ▁seized ▁the ▁opportunity ▁and ▁attacked ▁the ▁half ▁of ▁the ▁inv ading ▁army ▁that ▁had ▁not ▁yet ▁crossed . ▁Later ▁reports ▁by ▁chron ic lers ▁made ▁the ▁battle ▁into ▁a ▁mass acre , ▁but ▁contemporary ▁writers ▁bare ly ▁noticed ▁it . ▁Modern ▁histor ians ▁have ▁pra ised ▁William ' s ▁general ship ▁during ▁the ▁battle , ▁with ▁David ▁B ates ▁not ing ▁the ▁battle ▁as ▁an ▁example ▁of ▁William ' s ▁habit ▁of ▁surprising ▁his ▁enemies ▁with ▁unexpected ▁moves . ▁ ▁The ▁main ▁effect ▁was ▁that ▁the ▁inv aders ▁retre ated ▁quickly ▁from ▁Norm andy . ▁The ▁battle ▁also ▁marked ▁the