However , Gim Gyeong - sin seized power by military force and became King Wonseong .
Gim 's father , Gim Ju - won , was first in line to take the Silla throne after the death of King Seondeok .
Gim Gyeong - sin seized power by military force and became King Wonseong .
Gim 's father , Gim Ju - won , was first in line to take the Silla throne after the death of King Seondeok .