Letters Patent

Letters Patent (from the Latin litterae patentes, meaning "open letters") are a type of legal instrument in the form of a published written order issued by a monarch, president, or other sovereign authority. Unlike "letters close," which were sealed and addressed to a specific recipient, letters patent are left open so that anyone may read them — a feature that historically gave them public, constitutive force.

Originating in medieval English chancery practice, letters patent have been used for a wide range of purposes:

• Creating peerages and titles of nobility, such as the elevation of an individual to a dukedom or barony in the United Kingdom.
• Appointing officials, including governors-general, judges, and ambassadors. For example, the Governor-General of Australia is appointed by the British monarch by letters patent, with the office itself constituted by the Letters Patent of 29 October 1900 (subsequently amended).
• Granting corporate charters, such as the original charter of the British East India Company (1600) and the Hudson's Bay Company (1670).
• Conferring exclusive rights to inventions, the origin of the modern term "patent" in intellectual property law. The English Statute of Monopolies 1624 limited the Crown's ability to issue letters patent for monopolies except for new inventions.
• Constituting territories and colonial governments, such as the letters patent establishing the office of Governor of Hong Kong during British administration.

In Commonwealth realms, letters patent remain a live constitutional instrument. They are typically issued under the Great Seal and signed by the sovereign or, by delegation, the relevant head of state. In republics, analogous instruments are often called commissions or decrees.

For researchers, letters patent are significant because they often serve as the foundational document defining the powers, succession, and limits of high constitutional offices — meaning their text, and any amendments, can have direct bearing on questions of executive authority and reserve powers.