Legal Definitions - ad jura regis

ad jura regis is a historical legal term from Law Latin, meaning "for the rights of the king." It refers to a specific type of legal action, known as a writ, that was used in historical English law. This writ was initiated by an individual who held a "royal benefice"—a position, property, or privilege that had been granted to them directly by the Crown or king. The purpose of the ad jura regis writ was to defend the holder's right to that benefice against someone attempting to unlawfully dispossess them or challenge their entitlement. Essentially, it was a legal mechanism to protect royal grants and uphold the king's authority in making them.

• Example 1: Defending a Royal Land Grant

  Imagine that King Edward III, in recognition of loyal service, grants Sir Reginald a significant estate, including its lands and the right to collect rents from its tenants. Years later, a powerful neighboring baron, Lord Fitzwilliam, attempts to seize a portion of this estate, claiming it historically belonged to his family. Sir Reginald, as the holder of a royal benefice (the land grant), would have been able to issue an ad jura regis writ. This legal action would assert his right to the land, not just based on his personal claim, but fundamentally on the king's original grant. By defending Sir Reginald's possession, the writ implicitly defended the king's authority to make such grants and ensured that royal decrees were respected.

• Example 2: Protecting an Appointed Office

  Consider a scenario in the 15th century where the King of England appoints Master Thomas as the Royal Forester for a vast royal hunting ground, a position that comes with specific duties, privileges, and a regular income. A local nobleman, seeking to expand his own influence, attempts to install his own man as Royal Forester, thereby challenging Master Thomas's royal appointment. Master Thomas, holding the office as a royal benefice, could have used an ad jura regis writ. This writ would challenge the nobleman's attempt to remove him, arguing that his right to the position and its associated benefits stemmed directly from the king's authority. The legal action would thus protect the king's prerogative to appoint officials and manage royal lands.

• Example 3: Upholding a Royal Privilege or Franchise

  During the medieval period, the Crown grants a specific town the exclusive right (a royal franchise) to hold an annual fair and collect tolls from merchants within a ten-mile radius. A nearby village, encouraged by a local lord, begins to host its own rival fair, directly infringing upon the town's royal privilege and diminishing its income. The town, as the holder of this royal benefice (the exclusive fair rights), could have sought an ad jura regis writ. This legal instrument would have been used to stop the rival fair, asserting that the town's right to operate the fair and collect tolls was a direct grant from the king, and therefore, challenging it was an infringement upon the king's rights and authority.