PRAEROGATIVA REGIS
praerogativa regis (pree-rog-<<schwa>>-tI-v<<schwa>> ree-jis). [Law Latin “of the Crown’s prerogative”] Hist. A declaration made at the time of Edward I (1272–1307) defining certain feudal and political rights of the Crown, including the right to wardship of an idiot’s lands to protect the idiot’s heirs from disinheritance or alienation. — Also termed de praerogativa regis (dee pree-rog-<<schwa>>-tI-v<<schwa>> ree-jis).
“The king’s right is distinctly stated in the document known as praerogativa Regis, which we believe to come from the early years of Edward I. The same document seems to be the oldest that gives us any clear information about a wardship of lunatics. The king is to provide that the lunatic and his family are properly maintained out of the income of his estate, and the residue is to be handed over to him upon his restoration to sanity, or, should he die without having recovered his wits, is to be administered by the ordinary for the good of his soul; but the king is to take nothing to his own use.” 1 Frederick Pollock & Frederic W. Maitland, The History of English Law Before the Time of Edward I 481 (2d ed. 1898).
[Blacks Law 8th]