Korea underwent drastic changes under Japanese rule. Even before the country was formally annexed by Japan in 1910, the Japanese caused the last ruling monarch, King Kojong, to abdicate the throne in 1907 in favor of his feeble son, who was soon married off to a Japanese woman and given a Japanese peerage. Japan then governed Korea under a residency general and subsequently under a governor general directly subordinate to Japanese prime ministers. All of the governor generals were high-ranking Japanese military officers.