io ▁ed ▁Uniti ▁borders ▁the ▁following ▁municipal ities : ▁Borg arel lo , ▁Born as co , ▁Gi uss ago , ▁P avia , ▁Sant ' A less io ▁con ▁V ial one , ▁Z ec con e . ▁ ▁History ▁ ▁San ▁Gen es io ▁is ▁mentioned ▁in ▁the ▁ 1 2 th ▁century ▁as ▁San ct us ▁Gen ex ius . ▁It ▁was ▁the ▁seat ▁of ▁a ▁parish ▁church ▁( p ieve ) ▁of ▁the ▁dioc ese ▁of ▁P avia . ▁Under ▁Gian ▁G ale azzo ▁Vis cont i ▁the ▁territory ▁of ▁San ▁Gen es io ▁was ▁included ▁in ▁the ▁vast ▁Vis cont i ▁Park , ▁extending ▁between ▁the ▁castle ▁of ▁P avia ▁and ▁the ▁Cert osa ▁and ▁included ▁in ▁a ▁wall ▁del im iting ▁its ▁per imeter . ▁The ▁wall ▁was ▁interrupted ▁at ▁certain ▁locations ▁by ▁gates ▁( porte ) ▁from ▁which ▁are ▁derived ▁the ▁names ▁of ▁Port a ▁P es car ina ▁and ▁Due ▁Por te , ▁two ▁of ▁ham lets ▁included ▁in ▁San ▁Gen es io ▁ed ▁Uniti ▁territory . ▁following ▁the ▁fall ▁of ▁the ▁S for za ▁the ▁park ▁was ▁neglect ed ▁and ▁decay ed , ▁although ▁its ▁area ▁was ▁still ▁identified ▁as ▁administrative ▁district ▁( Par co ▁Nu ovo ). ▁Until ▁the ▁ 1 8 th ▁century ▁San ▁Gen es io ▁was ▁a ▁f ief ▁of ▁the ▁Cert osa ▁ab bey . ▁ ▁In ▁the ▁territory ▁of ▁San ▁Gen es io ▁was ▁fought ▁the ▁Battle ▁of ▁P avia ▁of ▁ 1 5 2 5 ▁between ▁the