A corporation sole, the Crown is the legal embodiment of executive, legislative, and judicial governance in the monarchy of each country. These monarchies are united by the personal union of their monarch, but they are independent states. The concept of the Crown developed first in England as a separation of the literal crown and property of the nation state from the person and personal property of the monarch. It spread through English and later British colonisation and is now rooted in the legal lexicon of the United Kingdom, its Crown dependencies, and the other 15 independent realms. It is not to be confused with any physical crown, such as those of the British regalia.
The term is also found in expressions such as "Crown land", which some countries refer to as "public land" or "state land"; as well as in some offices, such as Minister of the Crown, Crown Attorney, and Crown Prosecutor.
The concept of the Crown took form under the feudal system. Though not used this way in all countries that had this system, in England, all rights and privileges were ultimately bestowed by the ruler. Land, for instance, was granted by the Crown to lords in exchange for feudal services and they, in turn, granted the land to lesser lords. One exception to this was common socage—owners of land held as socage held it subject only to the Crown. When such lands become owner-less they are said to escheat; i.e., return to direct ownership of the Crown (Crown lands). Bona vacantia is the royal prerogative by which unowned property (primarily unclaimed inheritances) become the property of the Crown (except in Cornwall, where it becomes the property of the Duke of Cornwall or Lancashire where it becomes the property of the Duke of Lancaster).
The monarch is the living embodiment of the Crown and, as such, is regarded as the personification of the state. The body of the reigning sovereign thus holds two distinct personas in constant coexistence: that of a natural-born human being and that of the state as accorded to him or her through law; the Crown and the monarch are "conceptually divisible but legally indivisible ... he office cannot exist without the office-holder". The terms the state, the Crown, the Crown in Right of , Her Majesty the Queen in Right of , and similar are all synonymous and the monarch's legal personality is sometimes referred to simply as the relevant jurisdiction's name. (In countries using systems of government derived from Roman civil law, the State is the equivalent concept to the Crown.)
As such, the king or queen is the employer of all government officials and staff (including the viceroys, judges, members of the armed forces, police officers, and parliamentarians), the guardian of foster children (Crown wards), as well as the owner of all state lands (Crown land), buildings and equipment (Crown held property), state owned companies (Crown corporations), and the copyright for government publications (Crown copyright). This is all in his or her position as sovereign, and not as an individual; all such property is held by the Crown in perpetuity and cannot be sold by the sovereign without the proper advice and consent of his or her relevant ministers.