Donald Mormaer of Mar fought alongside the great Irish King Brian Boru against Norse invaders in 1014. ‘Rothri’ a later Mormaer is named in the charter erecting the abbey of Scone in 1114.
William, the 5th Earl was a regent of Scotland and Great Chamberlain of the Realm in 1264. He was a witness to the marriage of Princess Margaret and Eric King of Norway who’s daughter ‘The maid of Norway’ was tragically killed on her way to claim the throne, throwing Scotland into a great period of unrest.
Earls of Mar supported Robert the Bruce and were closely connected in marriage – William’s granddaughter was married to Robert while his Grandson, Gratney married Bruce’s sister. Gratney died around 1305 and his only son, Donald was kidnapped by the English and only released after the battle of Bannockburn in 1314 along with many of Bruce’s relatives in exchange for Earl of Hereford. Donald was later elected as Regent but was killed during a surprise attack by Edward Balliol’s English army at battle of Dupplin near Perth in 1332
The 9th Earl died with no heir and title passed to his sister and to her daughter Isabel. Isabel later married the Wolf of Badenonch Alexander Stewart. A rather shady character who had almost certainly been involved in the death of her first husband and who’s ‘wooing’ technique involved a prolonged siege! Isabel died with no children so title passed back to a descendant of the 7th Earl
James II intervened in later successions and claimed the Earldom for the crown through Alexander Stewart and so the Earldom passed into Stewart family. This unlawful succession was finally interrupted by Mary, Queen of Scots, who saw that the rightful heir John the 20th Earl was restored. John was governor of Edinburgh Castle and supported Charles I more by default than through any great allegiance and had his estates forfeited until the restoration of Charles II.
Their choice of allegiance landed them in trouble again in 1715 when John 23rd Earl and Duke of Mar had his honours forfeited for supporting the Jacobite cause of James VIII. These honours were restored in 1824 by Act of parliament.