Isabella Of Mar, born at Kildrummy Castle, Aberdeenshire in 1277, was the daughter of Domhnall I, the Earl of Mar, and Elen ferch Llywelyn (the illegitimate daughter of Llywelyn Fawr, famously known as Llywelyn the Great). Isabella, the Countess of Carrick, was a highly educated young woman for her time and spoke both English and Scots Gaelic fluently.
Her father, Domhnall I, the Earl of Mar, was a provincial ruler and the second in charge to the King of Scotland. He was knighted by King Alexander III of Scotland in 1270. Being one of the seven guardians of Scotland, he saw the opportunity for his heirs to inherit the throne if the Mar family formed an alliance with the Robert Bruce family. Robert the Bruce; Earl of Carrick, was believed to be the rightful king of Scotland following the death of King Alexander III’s heir Margaret (Maid of Norway ), and Domhnall Earl of Mar sought to tie the two families together through marriage.
At the age of 18 years, Isabella; heiress to a large part of Northeastern Inverness, was given away in marriage to Robert Bruce. To seal the arranged marriage, her father signed over the family estates to Robert Bruce. Legend has it that the young couple were deeply in love unlike most arranged marriages, and Isabella got pregnant soon after the wedding. Unfortunately, at the age of 19 years, Isabella died at the Manor of Cardross on the Firth of Clyde during childbirth on December 12, 1296. Her newborn daughter was named Marjorie, in honour of Bruce’s mother.
Isabella of Mar never became queen of Scotland as it was not till 10 years later that Robert Bruce was crowned King Robert I (the Bruce) of Scotland in 1306. By this time, Robert Bruce had gotten remarried to Elizabeth de Burgh with whom he had David II of Scotland, Elizabeth Bruce, Robert Bruce (Lord of Liddesdale), and Nail Bruce of Carrick.
Isabella and Robert Bruce’s daughter Marjorie married Walter Stewart (6th High Stewart of Scotland) in 1315, and together they had a son who eventually became King Robert II of Scotland. Marjorie, like her mother Isabella of Mar, died at the age of 19, during childbirth. It is said that Marjorie was riding a horse while heavily pregnant in Gallowhill, Renfrewshire, and she was thrown to the ground when the horse got startled.
Isabella of Mar had at least five siblings; Gartnait (7th Earl of Mar) who married the sister of Robert the Bruce VII, Duncan (Husband to Christina, Lady of Garmoran of the clan Ruaidhri), Alexander, Marjory ( Wife to John Strathbogie, 9th Earl of Atholl), and Mary (Wife to Kenneth de Moravia, 4th Earl of Sutherland).
She is the grandmother of King Robert II of Scotland (First Monarch of the House of Stewart) who reigned from 1371 to 1390, and her descendants include the House of Stewart and all their successors on the thrones of Scotland and the royal families across Europe.
She was buried at Cluniac Paisley Abbey, Renfrewshire. Her tomb has not survived time.