▁retained ▁by ▁the ▁By z antine ▁Empire . ▁In ▁modern ▁times , ▁many ▁dioc eses , ▁though ▁later ▁sub div ided , ▁have ▁preserved ▁the ▁boundaries ▁of ▁a ▁long - van ished ▁Roman ▁administrative ▁division . ▁For ▁Ga ul , ▁Bruce ▁E ag les ▁has ▁observed ▁that ▁" it ▁has ▁long ▁been ▁an ▁academic ▁common place ▁in ▁France ▁that ▁the ▁medieval ▁dioc eses , ▁and ▁their ▁constitu ent ▁pag i , ▁were ▁the ▁direct ▁territorial ▁success ors ▁of ▁the ▁Roman ▁civ it ates ." ▁ ▁Modern ▁usage ▁of ▁' di oc ese ' ▁tends ▁to ▁refer ▁to ▁the ▁sphere ▁of ▁a ▁bishop ' s ▁juris diction . ▁This ▁became ▁common place ▁during ▁the ▁self - cons cious ▁" class ic izing " ▁struct ural ▁evolution ▁of ▁the ▁Carol ing ian ▁Empire ▁in ▁the ▁ 9 th ▁century , ▁but ▁this ▁usage ▁had ▁itself ▁been ▁evol ving ▁from ▁the ▁much ▁earlier ▁par och ia ▁(" par ish "; ▁Late ▁Latin ▁derived ▁from ▁the ▁Greek ▁ π α ρ ο ι κ ί α ▁par o ik ia ), ▁d ating ▁from ▁the ▁increasing ly ▁formal ized ▁Christian ▁authority ▁structure ▁in ▁the ▁ 4 th ▁century . ▁ ▁Arch di oc ese ▁ ▁Dioc eses ▁ruled ▁by ▁an ▁arch bishop ▁are ▁commonly ▁referred ▁to ▁as ▁arch di oc eses ; ▁most ▁are ▁metropol itan ▁sees , ▁being ▁placed ▁at ▁the ▁head ▁of ▁an ▁ecc les iast ical ▁province . ▁A ▁few ▁are ▁suff rag ans ▁of ▁a ▁metropol itan ▁see ▁or ▁are ▁directly ▁subject ▁to