Sir John Arundell (1576–1654), eldest son and heir, of Trerice, nicknamed "Jack-for-the-King", MP for Cornwall and for Tregony. He was an infant aged four on his father's death, and became a ward of the crown, which wardship was purchased by family trustees, including his brother-in-law Richard Carew. He inherited from his father the newly rebuilt mansion house at Trerice with over 2,000 acres in Cornwall, Devon, Somerset and Dorset, with a reversionary interest in a further 3,050 acres, dependent on the death of his half-cousin John V Arundell (died 1613) of Gwarnick. Following the death of the latter, he sought to obtain possession of his estates, including the former Beville seat of Gwarnick, then claimed by the Prideaux family. In 1615 he obtained a Chancery decree under which he agreed to pay the Prideauxs £550 to abandon their claims. However Richard II Prideaux (died 1617) refused to comply with the verdict and was sent to the Fleet Prison, where he probably remained until his death two years later. The 1615 agreement was finally implemented in 1622. In 1637 he finally extinguished the Prideaux claim by paying £80 to Sir Richard Prideaux (died 1667), MP, the son and heir of Jonathan Prideaux (died 1637), MP, son of Richard II.