Page "Saban of Baekje" Paragraph 1

According to the Samguk Sagi, Saban was found too young to rule and quickly succeeded ( the Samguk Yusa says deposed ) by King Goi, the younger brother of the 5th king Chogo.

This is interpreted by scholars as a power struggle within the court, and the rise of the Jin clan over the Hae clan.