) ▁in ▁present - day ▁Y ong ji . ▁ ▁Southern ▁& ▁Northern ▁ge ographical ▁regions ▁ ▁During ▁the ▁time ▁of ▁rival ▁dynast ies ▁in ▁the ▁Southern ▁and ▁Northern ▁D ynast ies ▁period , ▁the ▁Northern ▁Wei , ▁Western ▁Wei ▁and ▁Northern ▁Z hou ▁dynast ies ▁in ▁the ▁north ▁referred ▁to ▁Y ong z hou ▁as ▁to ▁the ▁en vir ons ▁of ▁Ch ang ' an ▁with ▁its ▁government ▁seat ▁at ▁Ch ang ' an , ▁while ▁the ▁Eastern ▁Jin ▁dynast y ▁and ▁the ▁Southern ▁D ynast ies ▁in ▁the ▁south ▁referred ▁to ▁Y ong z hou ▁as ▁the ▁en vir ons ▁of ▁X i ang y ang . ▁ ▁S ui ▁province ▁ ▁After ▁the ▁reun ification ▁of ▁China ▁by ▁the ▁S ui ▁dynast y , ▁Y ong ▁Province ' s ▁administrative ▁centre ▁was ▁perman ently ▁set ▁at ▁Ch ang ' an . ▁During ▁the ▁S ui ▁administrative ▁re forms ▁in ▁ 6 0 7 ▁to ▁transform ▁the ▁provincial ▁system ▁into ▁a ▁command ery ▁system , ▁Emperor ▁Yang ▁renamed ▁Y ong ▁Province ▁to ▁J ing z ha o ▁Command ery ▁( 京 <0xE5> <0x85> <0x86> 郡 ). ▁ ▁Tang ▁province ▁ ▁When ▁the ▁Tang ▁dynast y ▁was ▁established , ▁it ▁was ▁revert ed ▁for ▁some ▁time ▁back ▁to ▁Y ong ▁Province , ▁until ▁Emperor ▁X u anz ong ▁converted ▁it ▁again ▁to ▁J ing z ha o ▁Pref ect ure ▁( 京 <0xE5> <0x85> <0x86> 府 ). ▁ ▁Category : Pro vin ces ▁of ▁An cient ▁China ▁Category : Pro vin ces