The second Robert de Brus of Annandale, son of the preceding lord, married (1183) Isabel, daughter of William the Lion, obtaining as her dowry the manor of Haltwhistle in Tyndale. His widow married Robert de Ros in 1191. The uncertainty as to the dates of his father's death and his own has suggested a doubt whether he ever succeeded to the lordship. William de Brus, a brother, the next lord, died in 1215. The third Robert de Brus of Annandale, son of William, founded the claim of his descendants to the crown by his marriage with Isabel, second daughter of David, Earl of Huntingdon, younger brother of William the Lion. He died in 1245. The fourth Robert de Brus of Annandale, eldest son of the preceding lord, was born in 1210. In 1244, he married Isabel, daughter of Gilbert de Clare, Earl of Gloucester. Next year he succeeded to Annandale, and, on his mother's death in 1251, he obtained ten knight's fees in England, her share of the Earldom of Huntingdon. He took an active part in public affairs. In 1249-50 he sat as a Justice of the King's Bench, and in 1268 he became Chief Justice of England, but Edward, on his accession (1272), did not reappoint him. He served as Sheriff of Cumberland and Governor of Carlisle Castle in 1254-55, and in 1264 he fought for Henry at Lewes, and was taken prisoner. At the same time, de Brus was a prominent figure in the baronage of Scotland. The alleged arrangement of 1238 whereby Alexander II., with the consent of the Scots parliament, appointed de Brus his successor in the event of his dying childless, was frustrated by the King's second marriage (1239), and the birth of a son, Alexander III. (1241). As one of the fifteen Regents (1255) during the minority of Alexander III., he headed the party that favoured an English alliance, cemented by the young King's marriage with Margaret, daughter of Henry III. At the Scone convention on February 5, 1283-84, he was one of the Scots lords that recognised the right of Margaret of Norway. The sudden death of Alexander III., however, in March 1285-86, and the helplessness of the infant Queen, put him on the alert for the chances of his own elevation.