 Manila was occupied by British forces for twenty months , from <unk> to 1764 , and used as a base for an unsuccessful attempt to conquer the Philippines during the Seven Years ' War . Eventually , the British withdrew from Manila as per agreements in the 1763 Treaty of Paris . The Chinese were punished for supporting the British invasion , and the small fortress @-@ city of <unk> , mostly populated by Europeans and <unk> , kept its cannons pointed at <unk> , the world 's oldest <unk> . 
