Jumong grew up in Geumwa’s house. The king had seven sons and Daeso was the eldest. Growing up in the same yard, the difference in ability kept showing.
The sons resented him and told their father that Jumong had to be got rid of. The king did not dismiss what his sons said.
Instead the king set Jumong to tend the horses. It was a way of pushing him into the lowest position, and it is there that he sees what nobody else sees.