▁coming ▁from ▁that ▁province , ▁with ▁the ▁remainder ▁each ▁year ▁being ▁sent ▁to ▁the ▁central ▁government ▁in ▁Dam asc us . ▁As ▁the ▁central ▁power ▁of ▁the ▁Um ay y ad ▁r ul ers ▁w an ed ▁in ▁the ▁later ▁years ▁of ▁the ▁dynast y , ▁some ▁govern ors ▁neglect ed ▁to ▁send ▁the ▁extra ▁tax ▁re venue ▁to ▁Dam asc us ▁and ▁created ▁great ▁personal ▁fort unes . ▁ ▁Government ▁workers ▁As ▁the ▁emp ire ▁grew , ▁the ▁number ▁of ▁qualified ▁Arab ▁workers ▁was ▁too ▁small ▁to ▁keep ▁up ▁with ▁the ▁rapid ▁expansion ▁of ▁the ▁emp ire . ▁Therefore , ▁Mu aw i ya ▁allowed ▁many ▁of ▁the ▁local ▁government ▁workers ▁in ▁conquer ed ▁provinces ▁to ▁keep ▁their ▁jobs ▁under ▁the ▁new ▁Um ay y ad ▁government . ▁Thus , ▁much ▁of ▁the ▁local ▁government ' s ▁work ▁was ▁recorded ▁in ▁Greek , ▁Co ptic , ▁and ▁Pers ian . ▁It ▁was ▁only ▁during ▁the ▁reign ▁of ▁Abd ▁al - Mal ik ▁that ▁government ▁work ▁began ▁to ▁be ▁regularly ▁recorded ▁in ▁Arab ic . ▁ ▁C urrency ▁ ▁The ▁By z antine ▁and ▁S ass an id ▁Emp ires ▁re lied ▁on ▁money ▁econom ies ▁before ▁the ▁Muslim ▁con quest , ▁and ▁that ▁system ▁remained ▁in ▁effect ▁during ▁the ▁Um ay y ad ▁period . ▁By z antine ▁co pper ▁co ins ▁were ▁used ▁until ▁ 6 5 8 , ▁while ▁By z antine ▁gold ▁co ins ▁were ▁still ▁in ▁use ▁until ▁the ▁mon et ary ▁re forms ▁c . 7 0