thumb|200px|The frontispiece of Thomas Hobbes' Leviathan, depicting the Sovereign as a massive body wielding a sword and crozier and composed of many individual people.

Sovereignty is the right to exercise, within a territory, the functions of a state, exclusive of any other state, or Kingdom and subject to no other authority. . Online, Google Books entry A sovereign is a supreme lawmaking authority.

Classical

Ideas about sovereignty have changed over time. The Roman jurist Ulpian observed that:

• The imperium of the people is transferred to the Emperor,
• The Emperor is not bound by the law,
• The Emperor's word is law.

Ulpian was expressing — although he did not use the term — the idea that the Emperor exercised a rather absolute form of sovereignty. Ulpian's statements were known in medieval Europe but sovereignty was not 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.

Medieval

During the medieval period, sovereignty existed as the de jure rights of nobility and royalty, and in the de facto right and capability of an individual to make their own choices in life.

Around c. 1380-1400, the issue of feminine sovereignty was addressed in Geoffrey Chaucer's Middle English collection of Canterbury Tales, specifically in The Wife of Bath's Tale.

A later English Arthurian romance, The Wedding of Sir Gawain and Dame Ragnell (c. 1450) , uses much of the same elements of the Wife of Bath's tale, yet changes the setting to the court of King Arthur and the Knights of the Round Table. The story revolves around the knight Sir Gawain granting to Dame Ragnell, his new bride, what is purported to be wanted most by women: sovereignty.

Reformation

Sovereignty reemerged as a concept in the late 1500s, a time when civil wars had created a craving for stronger central authority, when monarchs had begun to gather power into 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; and Thomas Hobbes, partly in reaction to the English Civil War, both presented theories of sovereignty calling for strong central authority in the form of absolute monarchy. In his 1576 treatise 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 not 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 to 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: impossible if the governing power is absolute.