3 1 2 , ▁the ▁role ▁of ▁the ▁Pra et or ian ▁pre fect ▁in ▁the ▁Empire ▁became ▁purely ▁administrative , ▁r uling ▁large ▁territ ories ▁( p ref ect ures ) ▁compr ising ▁Roman ▁dioc eses ▁( ge ographical ▁sub div isions ▁of ▁the ▁Roman ▁Empire ) ▁in ▁the ▁name ▁of ▁the ▁Emperor . ▁ ▁Size ▁and ▁composition ▁ ▁The ▁Pra et or ian ▁C oh ort s ▁were ▁designated ▁as ▁Equ it ata e ▁( c aval ry ) ▁Tur ma e ▁( t ro ops ) ▁with ▁centuries ▁formed ▁of ▁inf antry , ▁initially ▁of ▁ 5 0 0 ▁men ▁each . ▁ ▁In ▁order ▁not ▁to ▁al ien ate ▁the ▁population ▁of ▁Rome , ▁while ▁conser ving ▁Republican ▁civil ian ▁trad itions , ▁the ▁Pra et ori ans ▁did ▁not ▁wear ▁their ▁arm or ▁while ▁in ▁the ▁heart ▁of ▁the ▁city . ▁Instead ▁they ▁often ▁wore ▁a ▁formal ▁to ga , ▁which ▁distinguished ▁them ▁from ▁civ ili ans ▁but ▁remained ▁in ▁a ▁respect able ▁civil ian ▁att ire , ▁the ▁mark ▁of ▁a ▁Roman ▁citiz en . ▁August us , ▁conscious ▁of ▁risk ing ▁the ▁only ▁military ▁force ▁present ▁in ▁the ▁city , ▁often ▁avoided ▁concentr ating ▁them ▁and ▁im posed ▁this ▁dress ▁code . ▁ ▁From ▁the ▁reign ▁of ▁T iber ius , ▁their ▁camp ▁was ▁situated ▁on ▁the ▁Qu ir inal ▁Hill , ▁outside ▁Rome . ▁In ▁ 2 6 ▁AD , ▁Se jan us , ▁Pra et or ian ▁pre fect , ▁and ▁the ▁favorite ▁of