philosopher king

noun2

1. •
   A hypothetical ideal ruler, trained in philosophy, who has a full understanding of the Platonic ideal of the Form of the Good, and uses this for the benefit of the state.
2. •
   (figurative) A very wise ruler.

   • But if the President was not the philosopher-king, what was he? After all he was a man who had spent much of his life at a University. — 1919