▁This ▁would ▁originally ▁have ▁been ▁a ▁favour ite ▁food ▁of ▁the ▁aff lu ent ▁far mer , ▁which ▁later ▁reached ▁the ▁tables ▁of ▁the ▁urban ▁b our ge ois ie ▁and ▁typical ▁restaur ants . ▁ ▁T rip as ▁à ▁mod a ▁do ▁Porto ▁( tri pe ▁with ▁white ▁be ans ) ▁is ▁said ▁to ▁have ▁origin ated ▁in ▁the ▁ 1 4 th ▁century , ▁when ▁the ▁Cast ili ans ▁laid ▁sie ge ▁to ▁Lis bon ▁and ▁block aded ▁the ▁Tag us ▁entrance . ▁The ▁Portuguese ▁chron ic ler ▁Fern ão ▁L op es ▁dram atically ▁rec ount s ▁how ▁star v ation ▁spread ▁all ▁over ▁the ▁city . ▁Food ▁prices ▁rose ▁astronom ically , ▁and ▁small ▁boys ▁would ▁go ▁to ▁the ▁former ▁whe at ▁market ▁place ▁in ▁search ▁of ▁a ▁few ▁gra ins ▁on ▁the ▁ground , ▁which ▁they ▁would ▁eager ly ▁put ▁in ▁their ▁mouth s ▁when ▁found . ▁Old ▁and ▁sick ▁people , ▁as ▁well ▁as ▁prost it utes , ▁or ▁in ▁short ▁anybody ▁who ▁would ▁not ▁be ▁able ▁to ▁aid ▁in ▁the ▁city ' s ▁defence , ▁were ▁sent ▁out ▁to ▁the ▁Cast ilian ▁camp , ▁only ▁to ▁be ▁returned ▁to ▁Lis bon ▁by ▁the ▁inv aders . ▁It ▁was ▁at ▁this ▁point ▁that ▁the ▁citizens ▁of ▁Porto ▁decided ▁to ▁organ ize ▁a ▁supply ▁fleet ▁that ▁managed ▁to ▁s lip ▁through ▁the ▁river ▁block ade . ▁Appar ently , ▁since ▁all ▁available ▁meat ▁was ▁sent ▁to ▁the ▁capital ▁for ▁a ▁while , ▁Porto ▁residents ▁were ▁limited ▁to ▁tri