Euphemia married John Bruce of Cultmalindie (c. 1507 – March 1546/1547), a descendant of Robert the Bruce; their five children were Laurence Bruce, Robert Bruce (born c. 1536), Henry Bruce (born c. 1538), James Bruce (born c. 1540) and Euphamie Bruce (born c. 1542). Euphemia was also a mistress of James V of Scotland, producing Robert Stewart, 1st Earl of Orkney, as well as another royal bastard who died in childhood. She died either in 1542, or after 1547: there is no firm evidence for any death date.
Euphemia appears to have been, in her own right, rather unimportant: the daughter of a minor noble, she married a minor member of the Bruce family, and many consider her to be only a passing fancy to James V (although if she conceived on two separate occasions by him then this would appear slightly misleading). However, her children and descendants were to be important in the history of the Shetland Islands and Orkney Islands. Euphemia’s two most significant children were Laurence Bruce and Robert Stewart. Their families were to become closely entwined in the Shetland Islands, of which Laurence Bruce was appointed Sheriff by his half-brother.
According to legend, many people in the Shetland Islands are descended from her; in particular, those named Bruce are supposed to be descended from her children by John Bruce.