hereditarius

There is indeed a charter of the Conqueror preserved by Dr. Hickes, (vol. i.) where he calls himself "rex hereditarius," meaning heir by will; but a prince possessed of so much power, and attended with so much success, may employ what pretence he pleases; it is sufficient to refute his pretences to observe, that there is a great difference and variation among historians with regard to a point which, had it been real, must have been agreed upon by all of them.

The History of England in Three Volumes, Vol.I., Part A. From the Britons of Early Times to King John David Hume 1743