Korea's military history spans thousands of years, beginning with the ancient nation of Gojoseon and continuing into the present day with the countries of North Korea and South Korea, and is notable for its many successful triumphs over invaders.
Throughout its history, Korea has boasted numerous exceptional leaders who gained outstanding victories against numerically superior enemies. Famed leaders credited with defending Korea against foreign invasions include: Eulji Mundeok of Goguryeo, who defeated Sui China during the Goguryeo–Sui War; Yeon Gaesomun of Goguryeo, who defeated Emperor Taizong of Tang China during the Goguryeo–Tang War; Kang Kam-ch'an of Goryeo, who defeated the Khitan Empire during the Goryeo-Khitan War; Ch'oe Yŏng and Yi Sŏng-gye of Goryeo, who defeated the Red Turbans during the Red Turban Invasions; and Yi Sun-shin of Joseon, who defeated the Japanese at sea during the Imjin War.
Other notable leaders include: Gwanggaeto the Great of Goguryeo, who created a great empire in Northeast Asia through conquest, and subjugated the other Korean kingdoms of Baekje, Silla and Gaya to bring about a brief unification of the Three Kingdoms of Korea; Geunchogo of Baekje, who captured Pyongyang and established overseas territories to control much of the Korean peninsula and dominate the seas; 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; Dae Jo-yeong, who created Balhae from Goguryeo's ashes and reconquered Goguryeo lands lost during the Goguryeo-Tang War; Jang Bogo of Later Silla, who created a maritime empire and commanded a powerful fleet; Wang Kŏn, who united the Later Three Kingdoms of Korea and established Goryeo as the successor to Goguryeo; and Yun Kwan of Goryeo, who defeated the Jurchens and constructed nine fortresses in Manchuria.
During the Cold War, South Korean troops actively participated in the Vietnam War, contributing the second largest foreign military contingent after the United States. North Korea also contributed soldiers, military equipment and advisors to several conflicts during the Cold War in support of the Communist bloc, including the Yom Kippur War, Ethiopian Civil War, and Ugandan Bush War.
Today, both North Korea and South Korea field some of the largest and most lethal armies in the world. On one hand, North Korea is widely suspected of having nuclear weapons, as well as other weapons of mass destruction. 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. The South Korean military enjoys military alliances with other countries, particularly the United States.
Timeline
Gojoseon
Gojoseon–Yan War - 4th century B.C.
Han conquest of Gojoseon – 109–108 BC
Buyeo
Mohe conquest
Proto–Three Kingdoms of Korea
Goguryeo
Continuous battles with the Four Commanderies of Han
Battle of Jwawon
Xuantu Conquest – 302
Lelang Conquest – 313
Daifang Conquest – 314
Gongsun Du's Campaign against Goguryeo – 190
Goguryeo-Wei War – 244
Xianbei Conquest
Khitan Conquest
Baekje
Malgal Conquest
Conquest of Mahan by Baekje
Silla
Conquest of Jinhan by Silla
Campaign with Gaya
Gaya
Campaign with Silla
Three Kingdoms Period
Goguryeo campaigns
Campaign of Geunchogo of Baekje: Conquest of Pyongyang
Baekje Campaign of Gwanggaeto the Great of Goguryeo
Attack from Gwanggaeto the Great of Goguryeo
Gaya confederacy Campaign
Goguryeo–Yamato War
Campaigns of Gwanggaeto the Great of Goguryeo
Xianbei Campaign
Malgal Conquest
Khitan Conquest
Buyeo Conquest
Goguryeo, Baekje–Silla Alliance War
Campaign of Jangsu of Goguryeo against Silla and Baekje
Invasion of Baekje–Silla alliance – 475
Campaign of Baekje–Silla–Gaya armies against Goguryeo
Battle of Gwansan – 554
Gaya confederacy Annexation – 532/562
Other conflicts
The Baekje Conquest of Tamna – 498
The Silla Conquest of Usan – 512
Goguryeo–Sui War (598–614)
Goguryeo–Sui War – 598
Goguryeo–Tang War (645–668)
First conflict of the Goguryeo–Tang War – 645
Battle of Ansi — 645
Battle of Mount Jupil — 645
Battle of Sasu — 662
Battle of Geumsan — 667
Including Goguryeo and Baekje alliance against Tang and Silla
Baekje–Tang War (660–663)
Baekje–Tang War – 660
Silla–Tang War (668–676)
Other rebellions from Baekje and Goguryeo people
Battle of Maeso fortress
North South States Period
Balhae
Battle of Tianmenling – War of Foundation – 698
Balhae expedition to Dengzhou – 732
Balhae-Silla Conflicts
Conquest of Balhae by Khitan – 926
Silla (676–935)
Campaigns of Jang Bogo
Kim Hŏn-ch'ang Rebellion
Red Pants Rebellion
Ungjin Commandery Conquest – 676
Gyerim Territory Area Command Conquest – 735
Protectorate General to Pacify the East Conquest – 773
Ajagae Rebellion
Ki Hwŏn Rebellion
Yang Kil Rebellion
Later Three Kingdoms – 900~936
Goryeo Dynasty
Goryeo wars
Northern Expansion of Manchuria
Goryeo-Khitan War
First conflict in the Goryeo–Khitan War
Second conflict in the Goryeo–Khitan War
Third conflict in the Goryeo–Khitan War (see also Battle of Gwiju)
Campaigns of General Yun Kwan against the Jurchens (see also Korean-Jurchen border conflicts)