 In the later 1330s Douglas continued to consolidate his powerbase in Southern Scotland using the Great Forest of Ettrick as cover to mount increasingly punishing raids upon the English, as had "The Good Sir James" before him.William Douglas seized control of Liddesdale from the English in 1337 and captured the following year, Hermitage Castle the key fortress in Liddesdale and over much of the Border country.Hermitage had been a royal castle under the Bruce, having been forfeited by Sir William de Soulis in 1320.