▁in ▁agricult ure ▁and ▁education , ▁as ▁well ▁as ▁in ▁public ▁works ▁and ▁communic ations . ▁A ▁naval ▁base ▁also ▁increased ▁interaction ▁between ▁local ▁Filip inos ▁and ▁American ▁sail ors ▁and ▁administr ators . ▁At ▁the ▁close ▁of ▁the ▁ 1 8 th ▁century , ▁there ▁were ▁ 2 9 ▁municipal ities ▁in ▁the ▁province ▁of ▁C ag ay an . ▁After ▁the ▁Philippines ▁came ▁under ▁American ▁so vere ig nt y ▁in ▁ 1 9 0 2 , ▁more ▁municipal ities ▁were ▁founded . ▁Since ▁then , ▁due ▁to ▁central ization ▁and ▁sh ifting ▁of ▁populations , ▁the ▁number ▁of ▁ ▁municipal ities ▁is ▁back ▁to ▁ 2 9 . ▁ ▁World ▁War ▁II ▁ ▁During ▁the ▁Second ▁World ▁War , ▁with ▁air ▁ra ids ▁by ▁Japanese ▁f igh ters ▁and ▁bom bers , ▁the ▁province ▁of ▁C ag ay an ▁suffered ▁much ▁destruction ▁by ▁bomb ing ▁and ▁later ▁invasion . ▁Japanese ▁Imperial ▁forces ▁entered ▁C ag ay an ▁in ▁ 1 9 4 2 . ▁While ▁under ▁the ▁Japanese ▁Occ up ation , ▁several ▁pre - war ▁inf antry ▁divisions ▁and ▁regular ▁units ▁of ▁the ▁Philipp ine ▁Commonwealth ▁Army ▁were ▁re - est ab lished ▁during ▁the ▁period ▁on ▁January ▁ 3 , ▁ 1 9 4 2 ▁to ▁June ▁ 3 0 , ▁ 1 9 4 6 . ▁They ▁established ▁general ▁headquarters , ▁cam ps ▁and ▁g arrison ed ▁troops ▁in ▁the ▁province ▁of ▁C ag ay an , ▁and ▁began ▁operations ▁against ▁the ▁Japanese ▁Occ up ation ▁forces