King Naemul (356–402) of the Kim clan…

King Naemul (356–402) of the Kim clan establishes a hereditary monarchy in Silla, eliminating the rotating power-sharing scheme.

The leader's title, now truly royal, becomes Maripgan (from the native Korean root Han or Gan, "leader" or "great", which was previously used for ruling princes in southern Korea, and which may have some relationship with the Mongol/Turkic title Khan).

Naemul's later reign is troubled by recurrent invasions by Wa (Japan) and the northern Malgal (Mohe) tribes, sometimes considered the ancestors of the Jurchens, modern-day Manchus and other Tungusic peoples.

This begins with a massive Japanese incursion in 364, which is repulsed with great loss of life.