Silla, although it was the smallest of the three kingdoms, was the first to form. Founded by Chin Han in 57 BC, it was tucked away in the agriculturally fertile southeast. It was also the weakest of the three kingdoms in military terms. Isolated geographically, the people had little threat of raids and attacks from hostile neighbors. The land was rich for farming, so its people did not have to rely upon raiding or conquering other clans in search for food, as did the other two kingdoms. They had a peaceful existence.
Silla became a refuge for people from the other two kingdoms who preferred to live under old clan customs rather than under authoritarian rule. Due to the efforts of its people, Silla gradually developed into a powerful entity on the peninsula. Silla's growth was further stimulated by the introduction of Buddhism in the fifth century AD by the noted monk, Won-hyo. The high spiritual values of Buddhism appealed more to the people than the native myths.
During this period, tribal deity worship declined on the Korean Peninsula due to the penetration southward from China of Confucianism, Taoism, and later Buddhism. These religions had varying degrees of importance in the development of thought during the Three Kingdom Era.