Dictionary of National Biography, 1885-1900/Mar, Thomas
MAR, THOMAS, thirteenth Earl of (d. 1377), was the son of Donald, twelfth earl [q. v.], and succeeded on his father's death in 1332, though probably still under age. He was one of the Scottish commissioners sent to Newcastle in 1351 to treat for peace with England, and for the release of David II, and was also one of the hostages for the payment of his ransom. In 1358 he was appointed great chamberlain of Scotland, but held the office only about a year. He entered into an agreement with Edward III of England at Westminster (24 Feb. 1359) whereby he promised to remain with and faithfully serve the king of England against all the world (David, king of Scots, excepted) in return for a pension of six hundred merks sterling yearly, with compensation if on account of this agreement he should lose his Scottish estates (Rotuli Scotia, i. 830). After this date he only occasionally appears in Scotland.
David II in 1361 seized Mar's castle of Kildrummy (Wyntoun, Cronykil, lib. viii. cap. xlv. 11. 113-28). According to 'Scalacronica' (pp. 202, 203), the seizure was due to a quarrel arising out of a single combat between Mar and Sir William Keith (d. 1407?) [q. v.] at Edinburgh, when Mar accused the king of unduly favouring Keith. He was to receive back the castle upon payment of 1,000l. Scots at the expiry of five years, and during that period, at least, it remained in the hands of the king (Exchequer Rolls of Scotland, ii. 164, 166).
Between 1357 and 1373 Mar had numerous passports from Edward for journeys through England and pilgrimages to France and elsewhere, and also for the transit of horses and cattle, in which he seems to have trafficked (Rotuli Scotia, i. 471, 807-960 passim). He attended so little to his Scottish duties that the parliament in 1369 declared him to be contumaciously absent (Acts of the Parliaments of Scotland, i. 149), and on his next visit to Scotland, in the following year, he was arrested and imprisoned in the Bass (Exchequer Rolls, ii. 357). In that year (1370), however, David II died, and Mar was present at Scone on 27 March 1371, when Robert II was crowned, and he affixed his seal to the deed of that date, which settled the order of succession (Acts of Parliament, i. 181). He founded an altar in the cathedral church of Aberdeen in honour of St. James (Antiquities of Aberdeenshire, i. 151).
In 1352 the earl married Lady Margaret Graham, countess of Menteith, and widow of Sir John Moray of Bothwell. He received a dispensation from Pope Clement VI in that year, and another from Pope Innocent VI in 1354 (Fraser, Red Book of Menteith, i. 121-30). But he divorced this lady 'at the instigation of the devil,' says Fordun's 'Continuator,' and upon entirely false pretences (Fordun, ed. Goodall, ii. 150). She had no children by him. He married, secondly, Lady Margaret Stewart, countess of Angus, but neither had he any issue by her, and on his death in 1377 the male line of the Celtic earls of Mar ended. He was succeeded in the earldom by his sister Margaret, countess of Douglas.
[Rymer's Fœdera, iii. 630-969 ; Bain's Calendar of Documents relating to Scotland, vol. iii. No. 1629, vol. iv. Nos. 27, 90, 101, 154; Antiquities of Aberdeenshire, vols. i-iv. passim.]