Joan Beaufort lived from about 1404 to 15 July 1445. Of English descent, she married James I of Scotland and was the mother of James II. The wider picture in Scotland at the time is set out in our Historical Timeline.
From the age of 12 in 1406, James I of Scotland spent 18 years of his life as a prisoner/guest/hostage in England. In 1423, James, by now aged 29, fell in love with Lady Joan Beaufort, a close relative of King Henry VI of England. Robert, Duke of Albany had died in 1420, to be replaced by his son Murdoch as Governor and Regent, and it seems likely that with James marrying into the family it was the English King Henry VI who took the initiative in negotiating a ransom for James's return under the terms of the Treaty of London of 4 December 1423.
James and Joan married in London on 12 February 1424. They then travelled north, and James I was finally crowned at Scone on 21 May 1424.
Joan accompanied James I when he eventually returned to Scotland in 1424. They had eight children together. Six of the children were girls, three of whom went on to marry the King of France, the Archduke of Austria and the Duke of Brittany. They also had twin boys, one of who died in infancy. The other was to become James II.
James I set about transforming his kingdom with a vigor that made him many enemies. To make things worse, doubts about the validity of the first marriage of James' grandfather, Robert II, raised questions about James' own right to the crown of Scotland. James found himself facing challenge from descendents of his grandfather's (unquestionably legal) second marriage.
On 20 February 1437, plotters supporting the claim to the throne of Walter, Earl of Atholl, a son of Robert II's second marriage, broke into the Blackfriars monastery in Perth where James I was staying with Queen Joan. James tried to escape by climbing down a sewer that exited onto the tennis court where he had spent many of his days. Ironically he had instructed that the outlet be blocked the previous day to prevent tennis balls being lost. James was cornered in the sewer and killed by Sir Robert Graham.
Queen Joan, though injured, escaped, and took their 6 year old son James - now James II - for safety to Stirling Castle. She then took immediate and dramatic steps to safeguard her son's hold on the throne by wiping out the side of Robert II's family responsible for murdering James I, with a savagery that was remarkable even for the times.
Joan was Regent of Scotland for her son until her marriage in 1439 to James Stewart, the Black Knight of Lorn. Thereafter she was sidelined from matters of state. She had three sons by her second marriage, who went on to become the 1st Earl of Atholl, the 1st Earl of Buchan, and the Bishop of Moray. She died in 1445.