King Jin Heung came to power in Silla in 540AD and called upon a Buddhist Priest, Won Kwang Bopsa to teach the martial arts to his noblemen. Won Kwang Bopsa developed a system of martial arts based on harmony with the laws of nature and a concept to unify the opposites embodied in the Yin Yang (day & night, anger & happiness, up & down, hard & soft, linear & circular). King Jin Heung's nobles were taught these martial arts along with the Buddhist faith to become warrior-intellectuals known as the Hwarang Warriors (Knights of the Flower). They lived by the warrior code as true martial artists for their dedication to duty and self-sacrifice resting on a goal greater than themselves.
Their superb war effort defeated Koguryo and Paekche, unifying Korea in 668 and ending the Three Kingdoms Period. The Silla Kingdom grew to become the longest sustaining dynasty in Asian history (992 years).
The Hwarang were also famous for their weapon systems in Gum (sword), Kal (knife), Jang Bong (long stick), Dan Bong (short stick), Sang Jul Bong (nunchaku), Chang (spear), Bu Chae (fan), Ji Pangee (cane) and the Gung Si (bow and arrow). The Korean sword art of Gumdo (way of the sword) is still very popular today, whilst other weapons have been integrated into various martial art systems including modern day Hapkido and DanTa.
After the fall of the Silla kingdom, Su Bak was split into more refined technical areas. Around 1100AD, the term Yu Sul (soft art) emerged as a name for soft style techniques such as those taught by Won Kwang Bopsa. It is said to have been described by throws, grappling, locks and attacks to vital points. The word "Yu Sul" is interpreted as "Jiu Jitsu" in Japanese. Sometime after 1400AD more refined empty-hand fighting systems evolved such as Kwon Bop which emerged and an umbrella term for hand striking techniques, Taekkyon was a system emphasising kicks. Both these ancient styles along with some others influenced modern day Tang Soo Do (way of the hand) born around 1947 and Tae Kwon Do (way of the hand and foot) born in 1955.
Taekkyon still exists today with a dance like appearance. It was modified as a folk dance during Japanese occupation in World War II as the Japanese wanted to outlaw all Korean martial arts, the locals continued to practice it as a dance, hiding it's devastating form. This shares a similar heritage to native Brazilian Capoeira. Today, Taekkyon is considered a Korean national treasure as the nation's longest preserved martial art, pictured below are GIANT Instructors Giorgio & Anthony Repice and students at the national Taekkyon HQ in 2008.