2 6 ▁February ▁ 3 6 4 . ▁As ▁he ▁prepared ▁to ▁make ▁his ▁acc ession ▁speech ▁the ▁soldiers ▁threatened ▁to ▁ri ot , ▁apparently ▁uncertain ▁as ▁to ▁where ▁his ▁lo y alt ies ▁lay . ▁Val entin ian ▁re ass ured ▁them ▁that ▁the ▁army ▁was ▁his ▁greatest ▁priority . ▁According ▁to ▁Am m ian us ▁the ▁soldiers ▁were ▁ast ounded ▁by ▁Val entin ian ’ s ▁bold ▁de mean or ▁and ▁his ▁willing ness ▁to ▁assume ▁the ▁imperial ▁authority . ▁To ▁further ▁prevent ▁a ▁succession ▁crisis ▁he ▁agreed ▁to ▁pick ▁a ▁co - August us . ▁His ▁decision ▁to ▁elect ▁a ▁fellow - em peror ▁could ▁also ▁be ▁constru ed ▁as ▁a ▁move ▁to ▁appe ase ▁any ▁opposition ▁among ▁the ▁civil ian ▁officials ▁in ▁the ▁eastern ▁portion ▁of ▁the ▁Empire . ▁By ▁agree ing ▁to ▁appoint ▁a ▁co - r uler , ▁he ▁assured ▁the ▁eastern ▁officials ▁that ▁someone ▁with ▁imperial ▁authority ▁would ▁remain ▁in ▁the ▁east ▁to ▁protect ▁their ▁interests . ▁ ▁Val entin ian ▁selected ▁his ▁brother ▁Val ens ▁as ▁co - August us ▁at ▁Constantin ople ▁on ▁ 2 8 ▁March ▁ 3 6 4 . ▁This ▁was ▁done ▁over ▁the ▁ob jections ▁of ▁D ag ala if us , ▁the ▁mag ister ▁equ it um . ▁Am m ian us ▁makes ▁it ▁clear ▁that ▁Val ens ▁was ▁sub ordinate ▁to ▁his ▁brother . ▁The ▁remainder ▁of ▁ 3 6 4 ▁was ▁spent ▁deleg ating ▁administrative ▁duties ▁and ▁military ▁commands . ▁According ▁to ▁the ▁ 5 th ▁century