1950 -- An Australian air force unit leaves for Korea to join the U.S.-led U.N. command that fought on South Korea's side in the 1950-53 Korean War. Shortly after the war broke out on June 25 with a North Korean invasion of South Korea, the U.N. Security Council passed a resolution to dispatch coalition forces to turn back the communist aggression.
The war ended with an armistice on July 27, 1953, but the conflict did not formally end since there was never a peace treaty between the two sides.
1957 -- The United Nations Command is relocated to Seoul from Tokyo as part of a U.S. move to forward deploy its troops and military assets in the Far East that eventually led to the U.S. entering the Vietnam War.
1965 -- The Cabinet decides to deploy combat troops to Vietnam to help the United States. The deployment was made in return for the U.S. provision of military equipment and a US$150 million loan.
A total of 312,000 South Korean troops fought alongside the U.S. military in the Vietnam War and about 5,000 of them died.
2003 -- South and North Korean officials meet in Paju, a South Korean border city 40 kilometers north of Seoul, to discuss reconnecting severed railways and roads across their heavily fortified border. The transportation links were cut just before the Korean War broke out on June 25, 1950. Construction of two sets of inter-Korean railways and roads was completed in late 2005, but the railways remain closed due to alleged North Korean military opposition.
2006 -- A South Korean boat leaves the port city of Busan to conduct a maritime survey of waters off the country's islets of Dokdo in the East Sea. Japan claims that Dokdo, believed to be rich in marine resources, is its territory.
2009 -- South and North Korea fail to make progress in their third round of talks, with their positions remaining wide apart over a joint industrial park and the fate of a detained worker.
2010 -- The U.N. Security Council debates the extent to which North Korea should be held responsible for the deadly sinking of a South Korean warship in March.
2014 -- A new law goes into effect in the U.S. state of Virginia, requiring local school textbooks to use the South Korean name "East Sea" alongside the more commonly used Japanese name "Sea of Japan" for the body of water between the two countries.