Army and warfare made their first appearance in Vietnamese history during the 3rd millennium BC. Throughout thousands of years, wars played a great role in shaping the identity and culture of people inhabited the land which is modern day Vietnam. Vietnam is regarded as one of the most militaristic countries in Southeast Asia, there is even a higher level belief Vietnam might be the most militaristic nation in Southeast Asia, and one of Asia and the world's most militaristic countries. The military history of the Socialist Republic of Vietnam began when Japan invaded French Indochina and soon defeated the French resistance. Since then, Vietnam has fought in many conflicts in Indochina.