His grandson, Sir John Arundell K.B., The Magnificent, K.B., The Magnificent,' was a great church benefactor (notably to the celebrated lost church of St. Piran-in-the-Sands - Perranzabulæ), and, according to his will, dated 18 April 1433, possessed no less than fifty-two complete suits of cloth of gold.
The Arundells acquired Lanherne by marriage with the heiress of that family; and they also formed, at different periods, alliances with the Carminows, the Grenvilles, the Bevils, the Lambournes, the Carews, the Trevanions, the Erisys, and other Cornish families.