As Imperial Prince Iyo, a son of Emperor Kanmu, was appointed to Dazai no sochi as an absentee official in 806, and the land system Kueiden was introduced in the district of Dazaifu in 823, it became a practice that the Imperial Prince (Imperial Prince Kazuwara at that time) was appointed Dazai no sochi just like Shinoninkoku and called 'Sochinomiya.'
大同_(日本)元年（806年）、桓武天皇の子・伊予親王が遙任で大宰帥に任じられ、弘仁14年（823年）の大宰府管区内での公営田設置を機に親王任国と同様に親王（当時は葛原親王）が任命されるのが慣例となり、こうした皇族を「帥宮（そちのみや）」と呼称した。