▁later ▁on . ▁ ▁At ▁the ▁beginning ▁of ▁the ▁ 2 nd ▁century , ▁It ali ans ▁made ▁up ▁ 8 9 % ▁of ▁the ▁Pra et or ian ▁Guard . ▁Under ▁Sept im ius ▁Sever us , ▁rec ruit ment ▁evol ved ▁to ▁author ize ▁the ▁inclusion ▁of ▁leg ion aries ▁of ▁the ▁Roman ▁army , ▁as ▁well ▁as ▁of ▁the ▁battle ▁hard ened ▁Army ▁of ▁the ▁Dan ube . ▁Sever us ▁station ed ▁his ▁supp or ters ▁with ▁him ▁in ▁Rome , ▁and ▁the ▁Pra et or ian ▁Gu ards ▁remained ▁loyal ▁to ▁his ▁choices . ▁ ▁Pra et or ian ▁Caval ry ▁ ▁Initial ly ▁each ▁coh ort ▁included , ▁as ▁for ▁a ▁Roman ▁leg ion , ▁a ▁caval ry ▁det achment ; ▁this ▁should ▁not ▁be ▁confused ▁with ▁the ▁equ ites ▁singular es ▁August i ▁who ▁appeared ▁under ▁the ▁em peror ▁Tra jan . ▁The ▁Pra et or ian ▁could ▁become ▁a ▁caval ry man ▁( E ques ) ▁after ▁almost ▁five ▁years ▁service ▁in ▁the ▁inf antry . ▁These ▁Pra et ori ans ▁remained ▁listed ▁in ▁their ▁Cent uries ▁of ▁origin , ▁but ▁operated ▁in ▁a ▁tur ma ▁of ▁ 3 0 ▁men ▁each ▁commanded ▁by ▁an ▁Opt io equ it um . ▁ ▁There ▁was ▁probably ▁one ▁tur ma ▁of ▁caval ry ▁for ▁two ▁centuries ▁of ▁inf antry . ▁Hence , ▁three ▁tur ma e ▁per ▁coh ort s ▁of ▁the ▁August an ▁period , ▁five ▁per ▁coh ort ▁in ▁ 1 0 0 ▁CE – 2