He resigned the Earldom in favour of his son William in 1476 , and lived another 8 years .
Exchanging his inherited lordship of Nithsdale for lands in Caithness , William was granted the hereditary title Earl of Caithness .
William resigned the Earldom in favour of William 's William William in 1476 , and lived another 8 years .
Exchanging his inherited lordship of Nithsdale for lands in Caithness , William was granted the hereditary title Earl of Caithness .