expression, ichidan verb
rise to the highest possible rank; reach the pinnacle of one's career
A formal, somewhat literary set phrase used to describe someone achieving the top position in a hierarchy, especially in historical or political contexts. Often implies reaching the rank of chief minister or equivalent.
彼は若くして位人臣を極めた。
He rose to the highest rank at a young age.
歴史上、位人臣
Throughout history, few people have reached the pinnacle of power.