1 5 6 8 . ▁ ▁The ▁invasion ▁f ared ▁well ▁initially . ▁Both ▁arm ies ▁over c ame ▁S iam ese ▁def enses ▁and ▁arrived ▁before ▁Ay ut th aya ▁by ▁December . ▁But ▁the ▁arm ies ▁were ▁not ▁ready ▁for ▁a ▁long - term ▁sie ge ▁of ▁the ▁heavily ▁fort ified ▁capital . ▁Because ▁of ▁poor ▁planning , ▁the ▁troops ▁began ▁dying ▁in ▁thousands ▁" from ▁want ▁and ▁expos ure " ▁by ▁February ▁ 1 5 8 7 . ▁By ▁March , ▁the ▁sie ge ▁began ▁to ▁fal ter , ▁and ▁supplies ▁stream ed ▁into ▁Ay ut th aya ▁through ▁g aps ▁in ▁the ▁Bur m ese ▁lines . ▁The ▁Bur m ese ▁forces ▁began ▁their ▁pain ful ▁withdraw al ▁on ▁, ▁being ▁ch ased ▁throughout ▁by ▁the ▁enemy . ▁Only ▁a ▁small ▁portion ▁of ▁the ▁original ▁army ▁made ▁it ▁back ▁across ▁the ▁border . ▁ ▁Third ▁Camp aign ▁( 1 5 9 0 - 1 5 9 2 ) ▁When ▁N anda ▁Bay in ▁had ▁placed ▁his ▁sons ▁as ▁govern ors ▁of ▁A va ▁and ▁P rome , ▁he ▁planned ▁to ▁res ume ▁the ▁war ▁against ▁S iam . ▁The ▁Bur m ese ▁were ▁able ▁to ▁raise ▁their ▁largest ▁force , ▁ 3 0 , 0 0 0 ▁men . ▁But ▁the ▁powerful ▁Sh an ▁state ▁of ▁M oga ung ▁had ▁revol ted , ▁ref using ▁to ▁contribute ▁its ▁qu ota . ▁Instead ▁of ▁foc using ▁on ▁M oga ung , ▁the ▁king ▁decided ▁to ▁w age ▁war ▁on ▁two