The writings of Jean Bodin provides us with an early theorisation of the idea of sovereignty even though the examples he uses are quite extensive. Essential to Bodin's notion of sovereignty is that the power the sovereign holds must be absolute and permanent. If a ruler holds absolute power for the duration of his life he can be said to be sovereign. In contrast, an elected official or some other person that holds limited powers can not be described to be sovereign. Although at times Bodin suggests that the people are sovereign, his definition of sovereignty as absolute, unlimited and enduring power points purposively towards a positive association of sovereignty and a singular monarchical, or even tyrannical, power.
Another qualification that Bodin introduces into the definition of sovereignty as absolute and perpetual is one that will become increasingly important in subsequent theorisations, culminating in the work of Carl Schmitt. For Bodin, a sovereign prince is one who is exempt from obedience to the laws of his predecessors and more importantly, those issued by himself. Sovereignty rests in being above, beyond or excepted from the law. Although it occupies a subordinate place in Bodin's theorisation, it could be said that this exception from being subject to the law is the quintessential condition of sovereignty in so far as it is understood politically.
Although for Bodin sovereignty is characterised by absolute and perpetual power he goes on to make a series of important qualifications to this concept. These come from two principle concerns. The first is real politics - Bodin seems to be aware that absolute power could licence behaviour injurious to sovereign authority. Hence for example a sovereign cannot and should not confiscate property nor break contractual agreements made with other sovereigns, estates nor private persons. The second reason is Bodin's underlying theological notion of divine authority and natural law. A sovereign may put aside civil law, but he must not question natural law (in which it appears right of property is sanctioned). Saying this, it is ultimately from this divine authority that the earthly right of sovereign power is legitimated. The prince literary does god's bidding, and yet by virtue of this can do wrong. Hopefully this helps out some :)
