▁faith ▁during ▁the ▁V andal ▁invasion ▁and , ▁in ▁its ▁isol ation , ▁was ▁dis posed ▁to ▁rest ▁on ▁outside ▁support , ▁gave ▁Leo ▁an ▁opportunity ▁to ▁assert ▁his ▁authority ▁there . ▁In ▁ 4 4 6 ▁he ▁wrote ▁to ▁the ▁Church ▁in ▁Ma ure t ania ▁in ▁regard ▁to ▁a ▁number ▁of ▁questions ▁of ▁discipline , ▁stress ing ▁the ▁point ▁that ▁lay men ▁were ▁not ▁to ▁be ▁appointed ▁to ▁the ▁epis cop ate . ▁ ▁In ▁a ▁letter ▁to ▁the ▁b ish ops ▁of ▁Camp ania , ▁Pic enum , ▁and ▁T usc any ▁( 4 4 3 ) ▁he ▁required ▁the ▁observ ance ▁of ▁all ▁his ▁pre cept s ▁and ▁those ▁of ▁his ▁prede cess ors ; ▁and ▁he ▁sharp ly ▁re bu ked ▁the ▁b ish ops ▁of ▁Sic ily ▁( 4 4 7 ) ▁for ▁their ▁deviation ▁from ▁the ▁Roman ▁custom ▁as ▁to ▁the ▁time ▁of ▁bapt ism , ▁requiring ▁them ▁to ▁send ▁deleg ates ▁to ▁the ▁Roman ▁syn od ▁to ▁learn ▁the ▁proper ▁practice . ▁ ▁Because ▁of ▁the ▁earlier ▁line ▁of ▁division ▁between ▁the ▁western ▁and ▁eastern ▁parts ▁of ▁the ▁Roman ▁Empire , ▁Il ly ria ▁was ▁ecc les iast ically ▁subject ▁to ▁Rome . ▁Pope ▁In noc ent ▁I ▁had ▁constit uted ▁the ▁metropol itan ▁of ▁Th ess al onica ▁his ▁vic ar , ▁in ▁order ▁to ▁opp ose ▁the ▁growing ▁influence ▁of ▁the ▁patri arch ▁of ▁Constantin ople ▁in ▁the ▁area . ▁In ▁a ▁letter ▁of ▁about ▁ 4 4 6 ▁to ▁a ▁successor ▁bishop