From the ashes of the Roman Empire sprang the feudal states of Medieval Europe. The feudal states were really estates, for feudalism does not understand the meaning of statehood. With the fall of Rome, the idea of a central authority and sovereignty vanished.
The nobles and princes of the Germanic tribes carved out states and principalities of their own, big or small. But they did not possess absolute authority over their lesser nobles and princes.
Instead of it, they created bonds of loyalty based on reciprocal rights and duties between the lord and his vassal in the enjoyment of his fief or estate, for which the vassal rendered military duty and paid economic dues to his lord.