The first unified Korea was under the Silla, a Gyeongju-based empire that stretched over most of the peninsula. During this period arts, architecture, and culture flourished. The empire fragmented around AD 870, giving way to the Koryo dynasty, who allied themselves with the Song dynasty in China. The Koryo emulated the Song in establishing an advanced cultural and technological society (including the invention of printing in 1234, two centuries before its discovery in the West).
However, the peninsula fell to the Mongols in the 1230s. It took until the early 14th century, and the assistance of the Chinese Ming dynasty, to recover Korean independence. The Koryo dynasty was then followed in the late 14th century by the Choson who governed Korea until the early 20th century. The early years of the Choson saw Korea enter a period of outstanding cultural and intellectual achievement; however, during this time, the country suffered invasions by the Japanese and then the Chinese Manchu dynasty, which brought Korea under Chinese control and saw it remain, in effect, a satellite of the Chinese empire for almost 200 years. The shrines, palaces, and temples you visit today are almost all rebuilt from the ashes of originals that were burned to the ground.
At the end of WWII, as Japan was stripped of its colonial territories, the Soviets and Americans agreed to divide Korea along latitude 38°N (the 38th parallel). As the Cold War evolved, the Korean border - one of the few direct meeting points between the Soviet and American spheres of influence - became a key flashpoint. Cross-border incursions increased until full-scale war broke out between the two sides in 1950. The three-year war which followed engaged all the major powers and came closer than is often realised to provoking a nuclear conflagration. By 1953, a stalemate had been reached and an armistice was signed (although the war was never officially brought to an end and technically, the two countries are still at war). For the next three decades, locked into opposing Cold War blocs, the two Koreas went their separate ways.
South Korea developed a successful capitalist economy and current GDP stands at $1 trillion but until the early 1980s had failed to develop a political system of comparable sophistication – prior to then, South Korea was governed by a series of dictatorships, both civilian and military, under which political dissent led to imprisonment. However, at this point, the country's political leaders, with their powerbase in the monopolistic Democratic Justice Party, realised that some relaxation of the existing tight political control was necessary. In 1981, martial law was lifted and within five years, a powerful parliamentary opposition had emerged in the form of the New Korea Democratic Party (NKDP), led by the veteran dissident Kim Dae-Jung. However, it was not until December 1997 that Dae-Jung won the presidential poll.
In 2002, South Korea's international profile, as well as national morale, received a boost from co-hosting the World Cup football competition with Japan although this was marred by a political corruption scandal around the same time. Lee Myung-bak has been president since 2008, following the impeachment and subsequent suicide of previous president Roh Moo-hyun.
A slight thaw in North-South relations was followed in 2010 by the arrest of two US journalists and other events including the sinking of a South Korean warship (and the deaths of 46 sailors on board) and North Korean bombing of DMZ adjacent towns, has put any hopes of reunification on temporary hold.
Perhaps most importantly for those visiting Korea, history - both recent and ancient - remains very much a part of present day South Korea, something many Koreans feel strongly about, and especially after a few sojus have gone around, the topic can get heated.