Letters patent

Letters patent () (always in the plural) are a type of legal instrument in the form of a published written order issued by a monarch, president, or other head of state, generally granting an office, right, monopoly, title, or status to a person or corporation. Letters patent can be used for the creation of corporations or government offices, or for granting city status or a coat of arms. Letters patent are issued for the appointment of representatives of the Crown, such as governors and governors-general of Commonwealth realms, as well as appointing a Royal Commission. In the United Kingdom they are also issued for the creation of peers of the realm. 
A particular form of letters patent has evolved into the modern intellectual property patent (referred to as a utility patent or design patent in United States patent law) granting exclusive rights in an invention (or a design in the case of a design patent). In this case it is essential that the written grant should be in the form of a public document so other inventors can consult it both to avoid infringement and understand how to put it into practical use. In the Holy Roman Empire, Austrian Empire, and Austria-Hungary, imperial patent was also the highest form of generally binding legal regulations, e.g. Patent of Toleration, Serfdom Patent etc.
The opposite of letters patent are "letters close" (), which are personal in nature and sealed so that only the recipient can read their contents. Letters patent are thus comparable to other kinds of open letter in that their audience is wide. It is not clear how the contents of letters patent became widely published before collection by the addressee, for example whether they were left after sealing by the king for inspection during a certain period by courtiers in a royal palace, who would disseminate the contents back to the gentry in the shires through normal conversation and social intercourse. Today, for example, it is a convention for the British prime minister to announce that they have left a document they wish to enter the public domain "in the library of the House of Commons", where it may be freely perused by all members of parliament.
Meaning.
Letters patent are so named from the Latin verb "", to lie open, exposed, accessible. The originator's seal was attached "pendent" from the document, so that it did not have to be broken in order for the document to be read.
They are called "letters" (plural) from their Latin name "", used by medieval and later scribes when the documents were written in Latin. This loanword preserves the collective plural "letters" ("litterae") that the Latin language uses to denote a message as opposed to a single alphabet letter ("littera").
Usage.
Letters patent are a form of open or public proclamation and a vestigial exercise of extra-parliamentary power by a monarch or president. Prior to the establishment of Parliament, the monarch ruled absolutely by the issuing of his personal written orders, open or closed.
They can thus be contrasted with the Act of Parliament, which is in effect a written order by Parliament involving assent by the monarch in conjunction with its members. No explicit government approval is contained within letters patent, only the seal or signature of the monarch.
Parliament today tolerates only a very narrow exercise of the royal prerogative by issuance of letters patent, and such documents are issued with prior informal government approval, or indeed are now generated by government itself with the monarch's seal affixed as a mere formality. In their original form they were simply written instructions or orders from the sovereign, whose order was law, which were made public to reinforce their effect.
For the sake of good governance, it is of little use if the sovereign appoints a person to a position of authority but does not at the same time inform those over whom such authority is to be exercised of the validity of the appointment.
According to the United Kingdom Ministry of Justice, there are 92 different types of letters patent. The Patent Rolls are made up of office copies of English (and later United Kingdom) royal letters patent, which run in an almost unbroken series from 1201 to the present day, with most of those to 1625 having been published.
Commonwealth realms.
In Commonwealth realms, letters patent are issued under the prerogative powers of the head of state, as an executive or royal prerogative. They are a rare, though significant, form of legislation which does not require the consent of parliament. Letters patent may also be used to grant royal assent to legislation.
In the United States.
The primary source of letters patent in the United States are intellectual property patents and land patents, though letters patent are issued for a variety of other purposes. They function dually as public records and personal certificates.
In the United States, the forgery of letters patent granted by the President is a crime subject to fine, imprisonment up to ten years or both (). Without letters patent, a person is unable to assume an appointed office. Such an issue prompted the "Marbury v. Madison" suit, where William Marbury and three others petitioned the United States Supreme Court to order James Madison to deliver their letters for appointments made under the previous administration.
Form of United States letters patent.
United States letters patent generally do not fit a specific form, except for the eschatocol, or formal ending: