Treasonable practices against the life of Robert the Bruce brought about the downfall of the Celtic Earls. The Black Parliament, which sat at Scone in August, 1320, condemned Joanna, daughter of Malise, the last Earl, to perpetual imprisonment. She had married Warrenne, Earl of Surrey--appointed Guardian of Scotland by Edward I. in 1296--and in 1334 her father resigned his Earldom of Strathearn to his son-in-law. For the doing of this he was forfeited and attainted, in 1345, "as an enemy to the King and Kingdom of Scotland." The fief reverted to the Crown. Next year was fought the Battle of Durham, and David II. was carried captive to London, where he remained for eleven years. While in England he bestowed the forfeited Earldom of Strathearn upon his nephew, Robert, the High Steward of Scotland, afterwards King Robert II. On his accession to the throne, in 1370, Robert II. transferred the Earldom to David, the eldest son of his second marriage to Euphemia Ross, the widow of Randolph, Earl of Moray. Earl David took the title, Earl Palatine, in 1375, and his only daughter, Euphemia, who succeeded him in 1389, styled herself "_Senescalli Comitissa Palatina de Strathearn_." She married Patrick Graham, who was killed at Ferntower, in 1413, by Sir John Drummond of Concraig, Steward of Strathearn, and kinsman of James I., whose mother was Annabella Drummond. The only son of Patrick Graham and his wife, Euphemia, was Malise Graham, who, as Earl of Strathearn, became security along with twenty-seven others for the payment of the ransom of James I. He was detained as a hostage in England for thirty years, and meantime his estates and title were resumed by the King, on the ground that they did not descend to the heir-female. To compensate him for this, he was created Earl of Menteith. The annual rental of his estates as Earl of Strathearn was set down in the Durham Schedule at 500 merks. The schedule was drawn up in the year 1424.