ei et in eum omne suum imperium et potestatem conferat (Digest I.4.1) The laws do not bind the emperor. Princeps legibus solutus est (Digest I.3.31) A decision by the emperor has the force of law. Quod principi placuit legis habet vigorem. (Digest I.4.1) Ulpian was expressing the idea that the Emperor exercised a rather absolute form of sovereignty that originated in the people, although he did not use the term expressly. Medieval Ulpian's statements were known in medieval Europe, but sovereignty was an important concept in medieval times. Medieval monarchs were not sovereign, at least not strongly so, because they were constrained by, and shared power with, their feudal aristocracy. Furthermore, both were strongly constrained by custom. Sovereignty existed during the Medieval period as the de jure rights of nobility and royalty. Reformation Sovereignty reemerged as a concept in the late 16th century, a time when civil wars had created a craving for a stronger central authority when monarchs had begun to gather power onto their own hands at the expense of the nobility, and the modern nation state was emerging. Jean Bodin, partly in reaction to the chaos of the French wars of religion, presented theories of sovereignty calling for a strong central authority in the form of absolute monarchy. In his 1576 treatise Les Six Livres de la République ("Six Books of the Republic") Bodin argued that it is inherent in the nature of the state that sovereignty must be: Absolute: On this point, he said that the sovereign must be hedged in with obligations and conditions, must be able to legislate without his (or its) subjects' consent, must not be bound by the laws of his predecessors, and could not, because it is illogical, be bound by his own laws. Perpetual: Not temporarily delegated as to a strong leader in an emergency or a state employee such as a magistrate. He held that sovereignty must be perpetual because anyone with the power to enforce a time limit on the governing power must be above the governing power, which would be impossible if the governing power is absolute. Bodin rejected the notion of transference of sovereignty from people to the ruler (also known as the sovereign); natural law and divine law confer upon the sovereign the right to rule. And the sovereign is not above divine law or natural law. He is above (ie. not bound by) only