Margaret Tudor was Queen of Scots from 1503 until 1513 as the wife of King James IV of Scotland and then after her husband died whilst attempting to invade England she became regent for their son King James V. She was born at Westminster Palace as the elder surviving daughter of King Henry VII of England and Elizabeth of York and granddaughter of Margaret Beaufort. Margaret Tudor had many children but many also died young or were still-born. As queen dowager she married The 6th Earl of Angus. Through her first and second marriages, respectively, Margaret was the grandmother of both Mary, Queen of Scots, and Mary's second husband, Lord Darnley. Margaret's marriage to James IV foreshadowed the Union of the Crowns – their great-grandson, James VI and I, was the first to be king of both Scotland and England.

https://en.wikipedia.org/wiki/Margaret_Tudor