|via Wikimedia Commons|
Margaret was 13 when she married, and her 15-year-old husband was just leaving the control of regents to rule Scotland on his own. As was often the case in Scotland, his reign was a bit rocky. His ineffectual leadership did not help. So, it should come as no surprise that his younger brothers teamed up with those traditional enemies, the English, to oust James from his throne. The displacement was temporary--one brother was mysteriously killed and the other fled the country.
The big question is where Margaret fit into all of this family squabbling. Their relationship, although it produced three sons, had always been somewhat cool. Many believe that Margaret was more interested in preserving the rights of her children than assisting her husband. James seems to have gone a bit further, believing that Margaret was consorting with his enemies. Whatever the truth, their cool marriage turned even colder. It is not even clear whether they ever saw each other again after his restoration to power.
Margaret died only four years later, aged 30. She had been very popular among the Scots, who felt she was beautiful and sensible--and might have made a better king than her husband. Whispers of poisoning surrounded her death; an unpopular king is thought capable of many evil things, after all. Guilty conscious or not, James did apply to have his later wife canonized, an odd move considering his lack of affection during her life.
When James died following a battle two years later, their eldest son became King James IV at the age of 15, continuing a long line of childhood accessions in Scotland.
For more about Margaret:
Margaret of Denmark, Queen of Scotland on The Freelance History Writer
Margaret of Denmark, Queen of Scotland on Scottish Monarchs
1923 Book about Margaret: