▁any ▁historical ▁evidence ▁is ▁the ▁identification ▁of ▁Alc ara ▁with ▁the ▁gre co - By z antine ▁city ▁of ▁Dem en na ▁which ▁in ▁any ▁case ▁could ▁reason ably ▁be ▁local ized ▁in ▁the ▁area ▁of ▁the ▁Neb rod i , ▁including ▁the ▁area ▁between ▁San ▁Marco ▁d ' Al un z io , ▁Alc ara , ▁and ▁Long i . ▁Cont ro vers ial ▁also ▁is ▁the ▁local ity ▁of ▁the ▁gre co - s ican ian ▁city ▁of ▁C ras to ▁( K r ast os ) ▁which ▁according ▁to ▁various ▁local ▁histor ians ▁fl uct u ates ▁from ▁Western ▁Sic ily , ▁Southern ▁Sic ily , ▁and ▁Eastern ▁Sic ily , ▁but ▁that ▁should ▁not ▁devi ate ▁too ▁much ▁from ▁the ▁area ▁between ▁Agr ig ento ▁and ▁I mer a , ▁despite ▁the ▁presence ▁of ▁rock y ▁out cro ps ▁of ▁" C ras to " ▁just ▁above ▁the ▁habit ation ▁of ▁Alc ara . ▁ ▁According ▁to ▁local ▁or al ▁history , ▁which ▁takes ▁as ▁its ▁source ▁sch ol ars ▁of ▁the ▁ 1 6 th , ▁ 1 7 th , ▁and ▁ 1 8 th ▁centuries , ▁the ▁habit ation ▁would ▁have ▁its ▁origin ▁following ▁the ▁destruction ▁by ▁the ▁Sar ac ens ▁of ▁C ras to ▁and ▁Dé men a ▁in ▁ 8 5 5 . ▁ ▁Following ▁this , ▁a ▁part ▁of ▁the ▁inhabitants ▁transferred ▁to ▁an ▁area ▁more ▁within ▁the ▁valley . ▁ ▁The ▁same ▁version ▁of ▁the ▁story ▁is ▁given , ▁moving ▁a ▁little