6 1 5 ▁- ▁d . ▁Hof , ▁ 6 ▁February ▁ 1 6 5 1 ), ▁was ▁a ▁member ▁of ▁the ▁House ▁of ▁H oh enz oll ern ▁and ▁Her edit ary ▁Mar gra ve ▁( G erman : ▁Er b mark g raf ) ▁of ▁Brandenburg - B ay re uth . ▁ ▁He ▁was ▁the ▁sevent h ▁of ▁the ▁nine ▁children ▁of ▁Christian , ▁Mar gra ve ▁of ▁Brandenburg - B ay re uth ▁by ▁his ▁wife , ▁Marie ▁of ▁Pr uss ia . ▁In ▁fact , ▁he ▁was ▁the ▁third - born ▁son ▁but ▁the ▁only ▁one ▁to ▁surv ive ▁into ▁ad ul th ood ; ▁his ▁two ▁older ▁brothers ▁Georg ▁Frederick ▁( b . ▁and ▁d . ▁ 1 6 0 8 ) ▁and ▁Christian ▁Ernst ▁( b . ▁ 1 6 1 3 ▁- ▁d . ▁ 1 6 1 4 ) ▁died ▁long ▁before ▁his ▁own ▁birth . ▁ ▁In ▁Ans bach ▁on ▁ 8 ▁December ▁ 1 6 4 1 , ▁Erd mann ▁August ▁married ▁the ▁Mar gra v ine ▁Soph ie ▁of ▁Brandenburg - A ns bach , ▁who ▁was ▁also ▁his ▁first ▁cousin ▁( d augh ter ▁of ▁Jo achim ▁Ernst , ▁Mar gra ve ▁of ▁Brandenburg - A ns bach , ▁his ▁father ' s ▁brother ). ▁They ▁had ▁only ▁one ▁son : ▁ ▁Christian ▁Ernst ▁( b . ▁Bay re uth , ▁ 6 ▁August ▁ 1 6 4 4 ▁— ▁d . ▁Er lang en , ▁ 2 0 ▁May