1911 Encyclopædia Britannica, Volume 8… (1911)
“ The earldom and entailed estates of Douglas reverted by the patent of 1358 to Archibald Douglas, 3rd Earl of Douglas, called “The Grim” (c. 1328–c. 1400) , a natural son of the “good” Sir James. With his cousin, the 1st earl of Douglas, he had fought at Poitiers, where he was taken prisoner, but was released through ignorance of his real rank. On his return to Scotland he became constable and sheriff of Edinburgh, and, later, warden of the western marches, where his position was strengthened by his becoming lord of Galloway in 1369 and by his purchase of the earldom of Wigtown in 1372. ”
