▁Port ra its ▁of ▁Period ical ▁Of fer ing ▁() ▁was ▁a ▁series ▁of ▁official ▁historical ▁paint ings ▁( with ▁illustr ation ▁on ▁each ▁of ▁the ▁portrait ) ▁used ▁in ▁the ▁Chinese ▁dynast ies . ▁These ▁paint ings ▁were ▁official ▁historical ▁documents . ▁The ▁phrase ▁roughly ▁translated ▁to ▁" d ut y ▁offering ▁p ict orial ". ▁Through out ▁Chinese ▁history , ▁kingdom s ▁and ▁tribes ▁conquer ed ▁by ▁Chinese ▁forces ▁were ▁required ▁to ▁send ▁amb ass adors ▁to ▁the ▁imperial ▁court ▁of ▁China ▁period ically ▁and ▁pay ▁t ribute ▁with ▁valuable ▁g ifts ▁( <0xE8> <0xB4> <0xA1> 品 ▁g ong bin ). ▁ ▁Draw ings ▁and ▁paint ings ▁with ▁short ▁descri ptions ▁were ▁used ▁to ▁record ▁the ▁expression ▁of ▁these ▁amb ass adors ▁and ▁to ▁a ▁less er ▁extent ▁to ▁show ▁the ▁cultural ▁aspects ▁of ▁these ▁eth nic ▁groups . ▁These ▁historical ▁descri ptions ▁beside ▁the ▁portrait ▁became ▁the ▁equivalent ▁of ▁documents ▁of ▁diplom atic ▁relations ▁with ▁each ▁country . ▁The ▁draw ings ▁were ▁reprodu ced ▁in ▁wood block ▁printing ▁after ▁the ▁ 9 th ▁century ▁and ▁distributed ▁among ▁the ▁b ureau c racy ▁in ▁albums . ▁The ▁Port ra its ▁of ▁Period ical ▁Of fer ing ▁of ▁Imperial ▁Q ing ▁by ▁X ie ▁S ui ▁( <0xE8> <0xB0> <0xA2> <0xE9> <0x81> <0x82> ), ▁completed ▁in ▁ 1 7 5 1 , ▁gives ▁ver bal ▁descri ptions ▁of ▁out lying ▁tribes ▁as ▁far ▁as ▁the ▁island ▁of ▁Britain ▁in ▁Western ▁Europe . ▁ ▁The ▁Port ra its ▁of ▁Period ical ▁Of fer