Famed leaders credited with defending Korea against foreign invasions include: Eulji Mundeok of Goguryeo, who defeated Sui China during the Goguryeo–Sui War;[1] Yeon Gaesomun of Goguryeo, who defeated Emperor Taizong of Tang China during the Goguryeo–Tang War;[2][3] Kang Kam-ch'an of Goryeo, who defeated the Khitan Empire during the Goryeo-Khitan War;[4] Ch'oe Yŏng and Yi Sŏng-gye of Goryeo, who defeated the Red Turbans during the Red Turban Invasions;[5][6] and Yi Sun-shin of Joseon, who defeated the Japanese at sea during the Imjin War.
[7] Other notable leaders include: Gwanggaeto the Great of Goguryeo, who created a great empire in Northeast Asia through conquest,[8] and subjugated the other Korean kingdoms of Baekje, Silla and Gaya to bring about a brief unification of the Three Kingdoms of Korea;[9] Geunchogo of Baekje, who captured Pyongyang and established overseas territories to control much of the Korean peninsula and dominate the seas;[10][11] Munmu and Kim Yu-sin of Silla, who united the Three Kingdoms of Korea and defeated Tang China to gain complete control of the Korean peninsula;[12] Dae Jo-yeong, who created Balhae from Goguryeo's ashes and reconquered Goguryeo lands lost during the Goguryeo-Tang War;[13] Jang Bogo of Later Silla, who created a maritime empire and commanded a powerful fleet;[14] Wang Kŏn, who united the Later Three Kingdoms of Korea and established Goryeo as the successor to Goguryeo;[15] and Yun Kwan of Goryeo, who defeated the Jurchens and constructed nine fortresses in Manchuria.
[16] During the Cold War, South Korean troops actively participated in the Vietnam War, contributing the second largest foreign military contingent after the United States.
South Korea, for its part, is equipped with a sophisticated conventional military with state-of-the-art weapons.
South Korea currently serves in several UN peacekeeping missions around the world.